The CB1 cannabinoid receptors involvement in anti-epileptic effect of safranal on penicillin-induced epileptiform activity in rats.

Neuroprotective effects for natural products are supported by several studies. In this regard, safranal, a constitute of saffron, has the potential to exert beneficial effects in neuro-logical disorders such as Parkinson's disease, epilepsy, stroke, multiple sclerosis and Alzheimer's disease. Here, we investigated the effect of safranal on penicillin-induced epileptiform activity. Also, the effects of intracerebroventricular (ICV) microinjection of AM251 as a CB1-cannabinoid receptors antagonist to clarify the possible mechanism of safranal were evaluated. Epileptiform activity was induced by intra-cortical administration of penicillin (300 IU, 1.50 µL) in urethane-anesthetized rats. Electrocorticographic recordings were used to analyze the frequency and amplitude of spike waves. Intraperitoneal injections of safranal at doses of 1.00 and 4.00 mg kg-1 significantly reduced both the number and amplitude of spike waves. The ICV microinjection of AM251 (0.50 µg 2.00 µL-1) significantly increased the frequency and amplitude of spike waves. In addition, the anti-epileptic effect induced by administration of safranal at a dose of 4.00 mg kg-1 was partially prevented by ICV microinjection of 0.50 µg 2.00 µL-1 of AM251. The results showed anti-epileptiform activities for safranal. Central CB1 cannabinergic receptors might be involved in the anti-epileptiform activity of safranal.

Exogenous histamine and H 2 receptor activation and H 3 receptor inhibition in nucleus accumbens modulate formalin-induced orofacial nociception through opioid receptors.

It has been demonstrated that the nucleus accumbens (NAc) plays an important role in modulation of nociception due to its extensive connections with different regions of the brain. In addition, this nucleus receives histaminergic projections from tuberomammillary nucleus. Considering the role of the central histaminergic system in nociception, the effect of histamine and its H 2 and H 3 receptors agonist and antagonist microinjections into the NAc on orofacial formalin nociception was investigated. In male Wistar rats, using stereotaxic surgery, two guide cannulas were bilaterally implanted into the right and left sides of the NAc. Diluted formalin solution (1.5%, 50 µl) injection into the vibrissa pad led to orofacial nociception. Immediately after injection, face rubbing was observed at 3-min blocks for 45 min. Orofacial formalin nociception was characterized by a biphasic nociceptive response (first phase: 0-3 min and second phase: 15-33 min). Microinjections of histamine (0.5 and 1 µg/site), dimaprit (1 µg/site, H 2 receptor agonist) and thioperamide (2 µg/site, H 3 receptor antagonist) attenuated both phases of formalin orofacial nociception. Prior microinjection of famotidine (2 µg/site) inhibited the antinociceptive effects of dimaprit (1 µg/site). Furthermore, comicroinjection of thioperamide (2 µg/site) and immepip (1 µg/site) prevented thioperamide (2 µg/site)-induced antinociception. Naloxone (2 µg/site) also prevented histamine, dimaprit- and thioperamide-induced antinociception. The results of this study demonstrate that at the level of the NAc, histamine and its H 2 and H 3 receptors are probably involved in the modulation of orofacial nociception with an opioid system-dependent mechanism.

Cerebellar fastigial nucleus histamine and its H2 but not H1 receptors might inhibit acetic acid-induced visceral nociception and improve motor coordination in rats: role of opioid system.

The cerebellum and its deep nuclei contribute to the regulation of important functions including motor coordination and pain. Histamine modulates some functions of the fastigial nucleus (FN) such as motor coordination. In this study, by application of histamine and activation of its H1 and H2 receptors, the FN processing of visceral pain, general locomotor activity and motor coordination were targeted. The possible mechanism of action was followed by the inhibition of opioid receptors. The right and left sides of the FN were surgically implanted with guide cannulas. Immediately after an intraperitoneal injection of acetic acid (1.00 mL, 1.00%), the first writhing onset latency and the writhing number over 60 min were recorded. Open-field and rotarod tests were applied for general locomotor and motor coordination assessment, respectively. Histamine and dimaprit (H2 receptor agonist) increased first writhing onset latency, decreased the writhing number and increased falling time from the rod. These effects were prevented by ranitidine (H2 receptor antagonist) pre-treatment. Significant alterations were not observed by histamine H1 receptor agonist (2-pyridylethylamine) and antagonist (mepyramine). Naloxone, with no effect on falling time from the rod, inhibited the antinociceptive effects of histamine and dimaprit. Beam break number was not affected by the above-mentioned treatments. Based on the results, it can be suggested that histamine H2, but not H1 receptors at the FN might have had an inhibitory role on acetic acid-induced visceral pain and improved motor coordination. The antinociception, but not motor coordination might be mediated by FN opioid receptors.

Histamine and its H 1 receptors in the ventral pallidum mediate formalin-induced pain-related behaviors through this region and spinal cord opioid receptors.

Many structures of the central nervous system recruit different neurotransmitters in pain processing. This study focused on the contribution of histamine and its H 1 receptors in the ventral pallidum (VP) in mediating pain-triggered behaviors. Intra-VP microinjection of histamine and 2-pyridylethylamine (2-PEA, a histamine H 1 receptor agonist) at the same doses of 0.5 and 1 µg/200 nl reduced both the first and second phases of licking/biting duration as well as flinching number induced by intra-plantar (ipl) injection of formalin (2.5%, 50 µl). Premicroinjection of mepyramine (a histamine H 1 antagonist, 2 µg/200 nl) into the VP antagonized the suppressive effects of 1 µg/200 nl histamine and 2-PEA on licking/biting and flinching behaviors. The possible mechanisms of the above-mentioned pain-reducing effects were followed by intra-VP and intrathecal administration of naloxone (an opioid receptor antagonist). Naloxone (2 µg/200 nl) preadministration into the VP inhibited attenuating effects of histamine and 2-PEA on both the licking/biting and flinching behaviors, whereas intrathecal injection of naloxone only inhibited their suppressing effects on flinching behavior. None of the treatments used in this study altered the animal's motor activity. The obtained results may reveal the role of histamine and its activated H 1 receptor in the VP in suppressing the pain behaviors caused by formalin. Opioid receptors in the VP and spinal cord may contribute to these functions.

Medial prefrontal cortex nitric oxide modulates neuropathic pain behavior through mu opioid receptors in rats.

Background: The neocortex, including the medial prefrontal cortex (mPFC), contains many neurons expressing nitric oxide synthase (NOS). In addition, increasing evidence shows that the nitric oxide (NO) and opioid systems interact in the brain. However, there have been no studies on the interaction of the opioid and NO systems in the mPFC. The objective of this study was to investigate the effects of administrating L-arginine (L-Arg, a precursor of NO) and N(gamma)-nitro-L-arginine methyl ester (L-NAME, an inhibitor of NOS) into the mPFC for neuropathic pain in rats. Also, we used selective opioid receptor antagonists to clarify the possible participation of the opioid mechanism. Methods: Complete transection of the peroneal and tibial branches of the sciatic nerve was applied to induce neuropathic pain, and seven days later, the mPFC was cannulated bilaterally. The paw withdrawal threshold fifty percent (50% PWT) was recorded on the 14th day. Results: Microinjection of L-Arg (2.87, 11.5 and 45.92 nmol per 0.25 µL) increased 50% PWT. L-NAME (17.15 nmol per 0.25 µL) and naloxonazine (an antagonist of mu opioid receptors, 1.54 nmol per 0.25 µL) inhibited anti-allodynia induced by L-Arg (45.92 nmol per 0.25 µL). Naltrindole (a delta opioid receptor antagonist, 2.45 nmol per 0.25 µL) and nor-binaltorphimine (a kappa opioid receptor antagonist, 1.36 nmol per 0.25 µL) were unable to prevent L-Arg (45.92 nmol per 0.25 µL)-induced antiallodynia. Conclusions: Our results indicate that the NO system in the mPFC regulates neuropathic pain. Mu opioid receptors of this area might participate in pain relief caused by L-Arg.

Behavioral and receptor expression studies on the primary somatosensory cortex and anterior cingulate cortex oxytocin involvement in modulation of sensory and affective dimensions of neuropathic pain induced by partial sciatic nerve ligation in rats.

BACKGROUND: Brain cortical areas are involved in processing of sensory, affective and cognitive aspects of pain. In the present study, microinjection effects of oxytocin and L-368,899 (an oxytocin receptor antagonist) into the primary somatosensory cortex (S1) and anterior cingulate cortex (ACC) were investigated on sensory and affective aspects of neuropathic pain. METHODS: Neuropathic pain was induced by partial sciatic nerve ligation (PSNL). Seven days later, right and left sides of S1 and ACC were surgically implanted with guide cannulas. Sensory (day 14) and affective (day 17) dimensions were recorded using von Frey filaments and place escape avoidance paradigm, respectively. The S1 and ACC oxytocin receptor protein expression were also determined. RESULTS: The S1 and ACC oxytocin suppressed PSNL-induced mechanical allodynia, whereas PSNL-induced aversion was attenuated by ACC oxytocin. In the S1, alone L-368,899 with no effect on aversion increased mechanical allodynia, whereas, in the ACC, this treatment increased both mechanical allodynia and aversion. Pre-treatment with L-368,899 prevented oxytocin-induced anti-allodynia and anti-aversion. Oxytocin and L-368,899 did not alter mechanical allodynia in intact and sham groups. All the above-mentioned treatments did not change crossing number. The density of oxytocin receptors in the S1 and ACC of PSNL group was increased 1.5-2 folds in comparison to intact and sham groups. CONCLUSIONS: The results of the present study explained that the ACC and S1 oxytocin ameliorated sensory component of neuropathic pain, whereas affective component was attenuated only by ACC oxytocin. These effects might be related to the PSNL-increased oxytocin receptor expression in the S1 and ACC.

Behavioral, histopathological, and biochemical evaluations on the effects of cinnamaldehyde, naloxone, and their combination in morphine-induced cerebellar toxicity.

Long-term morphine use for therapeutic approaches may lead to serious side effects. Several studies have suggested opioid antagonist and antioxidant therapy for reducing adverse effects of morphine. Cinnamaldehyde has a potent anti-oxidant property. In this study, separate and combined effects of cinnamaldehyde and naloxone (an opioid receptor antagonist) on behavioral changes and cerebellar histological and biochemical outcomes were investigated after long-term morphine administration. Seventy-eight rats were divided into two major morphine-treated and morphine-untreated groups. Morphine-treated group was subdivided into seven subgroups for receiving vehicle, normal saline, cinnamaldehyde (1.25, 5, and 20 mg/kg), naloxone, and cinnamaldehyde plus naloxone before morphine. Morphine-untreated group was subdivided into six subgroups and treated with vehicle, cinnamaldehyde (1.25, 5, and 20 mg/kg), naloxone, and their combination. Chemical compounds were administered for 28 consecutive days. Behavioral tests including footprint, rotarod, and beam balance tests were employed. Histopathological and biochemical alterations of cerebellum were determined. Body and cerebellum weights, stride width, time spent on the rotarod, Purkinje cell number, thickness of molecular and granular layers, superoxide dismutase (SOD), and total antioxidant capacity (TAC) decreased as a result of administrating morphine. Morphine increased beam transverse time, malondealdehyde (MDA), tumor necrosis factor-α (TNF-α), and caspase-3 levels. Histopathological changes such as cellular vacuolation and loss were also produced as a result of treatment with morphine. Cinnamaldehyde, naloxone, and their combination treatments improved all the above-mentioned alterations induced by morphine. We concluded that cinnamaldehyde produced a neuroprotective effect through anti-oxidant, anti-inflammatory, apoptotic, and probably naloxone-sensitive opioid receptor interaction mechanisms.

Effects of intraperitoneal and intracerebroventricular injection of cinnamaldehyde and yohimbine on blood glucose and serum insulin concentrations in ketamine-xylazine induced acute hyperglycemia.

This study was designed to investigate the effects of peripheral [intraperitoneal (IP)] and central [intracerebroventricular (ICV)] administration of cinnamaldehyde on concentrations of blood glucose and serum insulin in the acute hyperglycemia induced by ketamine/xylazine. Yohimbine (a α2-adrenoceptor antagonist) was used alone and in combination with cinnamaldehyde to explore the α2-adrenergic receptor contribution. A total of 48 rats were divided into eight groups with six rats in each for IP administration of normal saline, vehicle, cinnamaldehyde (25.00, 50.00 and 100 mg kg-1), yohimbine (0.50 and 2.00 mg kg-1) and cinnamaldehyde plus yohimbine. These rats were used again for ICV administration 15 days after the completion of IP experiment. During this 15 days period, the lateral ventricle of the brain was surgically cannulated for ICV administration of normal saline, vehicle, cinna-maldehyde (25.00, 50.00 and 100 µg per rat), yohimbine (5.00 and 20.00 µg per rat) and cinnamaldehyde plus yohimbine. Blood glucose levels were measured from tail blood using a glucometer and serum insulin concentrations were determined via enzyme-linked immune-sorbent assay kit. The increased levels of blood glucose and the decreased concentrations of serum insulin were significantly decreased and increased, respectively, by separate and combined IP and ICV administrations of cinnamaldehyde and yohimbine. The systemic effects of these chemical compounds were significantly greater than the central ones. Based on the results, it can be argued that cinnamaldehyde has a potential to induce anti-hyperglycemic and antihypoinsulinemic effects. Peripheral and central α2-adrenegic receptors might be involved in these effects of cinnamaldehyde.

Ventrolateral periaqueductal gray exogenous and endogenous histamine attenuates sciatic nerve chronic constriction injury-induced neuropathic pain through opioid receptors.

The aim of the present study was to investigate the effects of intra-ventrolateral periaqueductal gray (vlPAG) microinjection of histamine and thioperamide (a histamine H3 receptor antagonist/inverse agonist) on neuropathic pain. To explore the possible mechanism, naloxone was microinjected alone or in combination with histamine and thioperamide. Neuropathic pain was induced by the left sciatic nerve chronic constriction injury. Both the right and left sides of vlPAG of the brain were surgically cannulated. Cold allodynia and mechanical hyperalgesia were recorded by acetone evaporation and von Frey filament tests. Areas under curve of allodynia and hyperalgesia were calculated. Histamine (0.50 and 2.00 µg per site), thioperamide (4.00 µg per site) and thioperamide (4.00 µg per site) before histamine (2.00 µg per site) suppressed cold allodynia and mechanical hyperalgesia after microinjection into the vlPAG. Microinjection of naloxone (0.25 and 1.00 µg per site) into the vlPAG had no effect on cold allodynia and mechanical hyperalgesia. The anti-allodynic and anti-hyperalgesic effects induced by microinjection of histamine (2.00 µg per site) and thioperamide (4.00 µg per site) into the vlPAG were inhibited by prior microinjection of naloxone (1.00 µg per site) into the same site. The above-mentioned agents did not alter locomotor activity. Based on our present results, it was concluded that exogenous (by histamine microinjection) and endogenous (by thioperamide microinjection) histamine of the vlPAG might contribute to the descending pain control mechanisms through a naloxone-sensitive mechanism.

Central H2 histaminergic and alpha-2 adrenergic receptors involvement in crocetin-induced antinociception in orofacial formalin pain in rats.

Previous findings have shown that saffron (Crocus sativus L.) extract and its active constituents produce antinociceptive effects in the rat models of orofacial pain. In the present study, the central H2 histaminergic and alpha-2 adrenergic receptors involvement in crocetin-induced antinociception in orofacial formalin pain in rats was evaluated. The guide cannula was implanted into the fourth ventricle in ketamine-xylazine anesthetized rats. Subcutaneous injection of a diluted formalin solution (1.50%; 50.00 µL) into a vibrissae pad was used as a model of orofacial pain. Face rubbing behavior durations were recorded at 3 min blocks for 45 min. Formalin produced a biphasic pain response (first phase: 0-3 min and second phase: 15-33 min). Intra-fourth ventricle injections of crocetin (5.00 and 10.00 µg µL-1) suppressed, whereas yohimbine (10.00 µg µL-1) and naloxone (10.00 µg µL-1) increased the intensity of both phases of pain. Crocetin-induced antinociception was not prevented by central pretreatment with naloxone. However, the antinociceptive effect of crocetin (5.00 µg µL-1) was inhibited by prior administration of famotidine (10.00 µg µL-1) and yohimbine (10.00 µg µL-1). Our study showed that injection of crocetin into the cerebral fourth ventricle attenuated formalin-induced orofacial pain in rats. Central H2 histaminergic and alpha-2 adrenergic receptors, but not opioid receptors, might be involved in crocetin-induced antinociception.

Comparison of the effects of hydroalcoholic extract of Capparis spinosa fruit, quercetin and vitamin E on monosodium glutamate-induced toxicity in rats.

Capparis spinosa L. has many biological effects such as antioxidant properties. In the present study, we compared the effects of the hydro-alcoholic extract of Capparis spinosa fruit, quercetin (Q), and vitamin E (Vit E) on monosodium glutamate (MSG)-induced toxicity. The following groups were designed: Control groups (normal saline and/or corn oil); MSG group (4.00 g kg-1 MSG); MSG + low dose extract group (4.00 g kg-1 MSG with 100.00 mg kg-1 extract); MSG + high dose extract (HDE) group (4.00 g kg-1 MSG with 300.00 mg kg-1 extract); MSG + Q group (4.00 g kg-1 MSG with 10.00 mg kg-1 Q); MSG + Vit E group (4.00 g kg-1 MSG with 200.00 mg kg-1 Vit E). All chemicals were orally administered for 14 consecutive days. Tissue specimens from the heart, kidney, and liver tissues and blood samples were collected for histopathological and biochemical evaluations. The results showed that the MSG-induced tissue edema, congestion, and inflammatory cell infiltration were resolved by HDE, Q, and Vit E treatments. These chemicals also restored tissue malondialdehyde level and superoxide dismutase activity. Besides, alterations induced by MSG in serum levels of aspartate transaminase, alanine aminotransferase, urea, lactate dehydrogenase, and creatine kinase-MB were also resolved. It is concluded that Capparis spinosa fruit extract, Q and Vit E can produce approximately similar protective effects on tissue function through oxidative stress alleviation and antioxidant mechanisms restoration.

Medial prefrontal cortex diclofenac-induced antinociception is mediated through GPR55, cannabinoid CB1, and mu-opioid receptors of this area and periaqueductal gray.

Supraspinal mechanisms of non-steroidal anti-inflammatory drug (NSAID)-induced antinociception are not well understood. In the present study, the possible antinociceptive mechanisms induced by intra-medial prefrontal cortex (intra-mPFC) microinjection of diclofenac were investigated after blockade of GPR55, cannabinoid CB1, and mu-opioid receptors in this area and ventrolateral periaqueductal gray (vlPAG). For drug delivery, unilateral (left side) of mPFC and bilateral (right and left sides) of vlPAG were surgically cannulated. Formalin test was induced by subcutaneous injection of a diluted formalin solution into the right vibrissa pad. A typical biphasic (neurogenic and inflammatory phases) pain behavior was produced following formalin injection. Microinjection of diclofenac (2.5, 5, and 10 µg/0.25 µL) into the mPFC suppressed both phases of pain. Intra-mPFC microinjection of naloxonazine (a mu-opioid receptor antagonist, 1 µg/0.25 µL) and AM251 (a cannabinoid CB1 receptor antagonist, 1 µg/0.25 µL) increased both phases of pain intensity. In addition, intra-mPFC-microinjected diclofenac-induced antinociception was inhibited by prior intra-mPFC and intra-vlPAG administration of naloxonazine and AM251. On the other hand, intra-mPFC and intra-vlPAG microinjection of AM251 (0.25 µg/0.25 µL) decreased pain severity which was inhibited by prior administration of ML193. The above-mentioned drugs did not alter locomotor activity. In conclusion, diclofenac suppressed both the neurogenic and inflammatory phases of formalin-induced orofacial pain at the level of mPFC. GPR55, cannabinoid CB1, and mu-opioid receptors of the mPFC and vlPAG might be involved in the mPFC analgesic effects of diclofenac.

The effects of crocin, mesalazine and their combination in the acetic acid-induced colitis in rats.

Crocin, as a carotenoid compound of saffron, exerts a potent antioxidant property. Mesalazine is frequently used in the treatment of ulcerative colitis. This study investigated the effects of separated and combination treatments with crocin and mesalazine in a rat model of ulcerative colitis. Ulcerative colitis was induced by intra-colonic administration of acetic acid (4.00%, 1.00 mL) at 8 cm proximal of the anus. Normal saline, acetic acid, crocin (5.00, 10.00 and 20.00 mg kg-1), mesalazine (100 and 300 mg kg-1) and crocin (5.00 mg kg-1) plus mesalazine (100 mg kg-1) were administered after induction of colitis for eight days. Body weight, organosomatic index (OSI), macroscopic and microscopic evaluations of colon and measurement of malondialdehyde (MDA), superoxide dismutase (SOD), tumor necrosis factor-alpha (TNF-α) contents of colon tissue were determined on day eight after induction of colitis. Crocin (10.00 and 20.00 mg kg-1), mesalazine (300 mg kg-1) and crocin (5.00 mg kg-1) plus mesalazine (100 mg kg-1) significantly (p < 0.05) improved body weight and OSI and reduced macroscopic and microscopic scores. These treatments also significantly (p <0.05) recovered the increased levels of MDA and TNF-α as well as the decreased level of SOD in colon tissue. Crocin and mesalazine did not produce significant effects in intact rats. Based on the results, it is concluded that crocin and mesalazine produced protective effects on colon tissue via antioxidant and anti-inflammatory actions. In addition, a synergistic effect was observed between crocin and mesalazine in attenuating ulcerative colitis.

Medial prefrontal cortex oxytocin-opioid receptors interaction in spatial memory processing in rats.

Medial prefrontal cortex (mPFC), a forebrain structure, is involved in many brain functions such as learning and memory. In the present study, the effect of intra-mPFC microinjection of oxytocin, atosiban, morphine and naloxone was investigated on memory processing. Two guide cannulas were implanted into the right and left sides of the mPFC in ketamine and xylazine-anesthetized rats. To assess spatial memory function MWM test was performed by four training sessions of four trials. On day 5, a probe test was conducted after drugs microinjection. Significant differences were observed in learning activities during training days before microinjection of drugs. Intra-mPFC microinjections of oxytocin (5 and 10 ng/site) significantly increased memory related activities. This effect of oxytocin was inhibited by prior microinjection of atosiban (20 ng/site). On the other hand, morphine microinjection at doses of 5 and 10 µg/site into the mPFC significantly decreased memory related activities that were prevented by prior administration of naloxone (5 µg/site) and oxytocin (5 and 10 ng/site). In addition, intra-mPFC combined microinjections of low doses of oxytocin (2.5 ng/site) and naloxone (1 µg/site) improved memory function. By increasing the doses of oxytocin (5 ng/site) and naloxone (5 µg/site), a more documented improving effect was observed. These results showed that memory performance was impaired by activation of mPFC opioid receptors in rats. In addition, oxytocin in the mPFC improved memory function and prevented memory impairment-induced by morphine. Moreover, an interaction between oxytocin and opioid systems was also appeared in the present study.

Microinjection of histamine and its H3 receptor agonist and antagonist into the agranular insular cortex influence sensory and affective components of neuropathic pain in rats.

Many areas of the brain along with neurotransmitters involve in processing of nociceptive, emotional and cognitive dimensions of neuropathic pain. Brian neuronal histamine through H1, H2, H3 and H4 receptors mediates many physiological functions such as cognition, emotion and pain. In the present study we investigated the effects of intra-agranular insular cortex microinjection of histamine and its H3 receptor agonist and antagonist on sensory and affective aspects of neuropathic pain. Spared nerve injury model of neuropathic pain was used. Two guide cannulas were surgically implanted in the right and left sides of agranular insular cortex. Sensory component (mechanical hyperalgesia) was recorded by application of von Frey filaments onto the plantar surface of the hind paw. Area under curve of mechanical hyperalgesia was calculated. Affective aspect (place escape avoidance paradigm) was recorded using an inverse white/black chamber. Histamine (0.5, 1 and 2 µg/site) and thioperamide (a histamine H3 receptor antagonist, 4 µg/site) decreased, whereas immepip (a histamine H3 receptor agonist, 2 µg/site) increased the percentages of paw withdrawal frequency and time spent in white side of white/black box. Prior administration of thioperamide (4 µg/site) increased the suppressive effects induced by histamine and inhibited immepip (2 µg/site)-induced hyperalgesia and aversion. Based on the present results, it is concluded that histamine and its H3 receptor at the agranular insular cortex level may involve in modulation of sensory and affective components of neuropathic pain.

Safranal, a constituent of saffron, exerts gastro-protective effects against indomethacin-induced gastric ulcer.

AIMS: Several natural products have been evaluated for management of gastric ulcer induced by non-steroidal anti-inflammatory drugs. Safranal, a plant-derived chemical, has a potent antioxidant and anti-inflammatory properties. The present study was aimed to evaluate possible gastro-protective effects of safranal against indomethacin-induced gastric ulcer in rats. Lansoprazole (a proton pump inhibitor) was used as a reference drug. MATERIALS AND METHODS: Thirty rats were divided into five groups. Groups 1 and 2 received vehicle. Groups 3, 4 and 5 treated with 0.063, 0.25 and 1 mg/kg safranal. Group 6 received 30 mg/kg lansoprazole. All groups except of group 1 received indomethacin (50 mg/kg) ingestion. Six hours later, animals were euthanized and their stomachs were removed. Gastric contents volume and pH were measured. Gastric ulcer area and protective index were evaluated using image J software. Histological changes were evaluated by light microscope. Malondialdehyde (MDA) level, superoxide dismutase (SOD) activity, total antioxidant capacity (TAC) content, tumor necrosis factor-alpha (TNF-α) and Caspase-3 levels were determined in the gastric tissue. KEY FINDINGS: Safranal and lansoprazole normalized gastric volume and pH, reduced gastric ulcer area and produced gastric protection. Indomethacin-induced histological changes and tissue biochemical alterations were ameliorated by the above-mentioned treatments. SIGNIFICANCE: The results of the present study suggest the involvement of anti-secretory, anti-oxidant, anti-inflammatory and anti-apoptotic mechanisms in gastro-protective effect of safranal. In addition, gastro-protective effect of safranal was comparable to lansoprazole.

Crocin exerts improving effects on indomethacin-induced small intestinal ulcer by antioxidant, anti-inflammatory and anti-apoptotic mechanisms.

Crocin is a plant-derived carotenoid and bears potent antioxidant property. Ranitidine (a histamine H2 receptor blocker) is used for peptic ulcer treatment. The present study was planned to investigate the effects of crocin and ranitidine on indomethacin-induced ulcer in small intestine of rats. Animals were randomized into two major groups including indo-methacin (10.00 mg kg-1, ulcer group, 48 rats) and normal saline (1.00 mL kg-1, intact group, 48 rats) groups. Each of these two major groups was subdivided into eight subgroups for intra-peritoneal (IP) injections of normal saline, crocin (2.50, 10.00 and 40.00 mg kg-1), ranitidine (5.00 and 20.00 mg kg-1), crocin (2.50 and 10.00 mg kg-1) plus ranitidine (5.00 mg kg-1). Indomethacin induced intestinal ulcer was characterized by bleeding, inflammation, epithelial hyperplasia and crypt loss. This non-steroidal anti-inflammatory drug (NSAID), indomethacin decreased goblet cell number and superoxide dismutase (SOD) activity and increased small intestine weight, organo-somatic index (OSI), malodealdehyde (MDA), tumor necrosis factor-α (TNF-α) and caspase-3 contents of intestine. Crocin resolved all the above-mentioned parameter changes induced by indomethacin. These treatments produced no significant effects on the above-mentioned parameters of intact group. The results of the present study showed tissue protective and anti-ulcer effects of crocin on small intestine by antioxidant, anti-inflammatory and anti-apoptotic mechanisms. Ranitidine alone showed no effect; however, in combination with crocin it exerted recovery effects. It is recommended that crocin, be considered as a therapeutic agent for NSAIDs-induced intestinal damage management.

Carnosine improves functional recovery and structural regeneration after sciatic nerve crush injury in rats.

AIMS: Peripheral nerve injury represents a substantial clinical problem with insufficient or unsatisfactory treatment options. Current researches have extensively focused on the new approaches for the treatment of peripheral nerve injuries. Carnosine is a naturally occurring pleotropic dipeptide and has many biological functions such as antioxidant property. In the present study, we examined the regenerative ability of carnosine after sciatic nerve crush injury using behavioral, biochemical, histological and ultrastructural evaluations. MATERIALS AND METHODS: Seventy-two rats were divided into six groups including control, sham, crush and carnosine (10, 20 and 40 mg/kg) groups. Crush injury in left sciatic nerve was induced by a small haemostatic forceps. Carnosine was administered for 15 consecutive days after induction of crush injury. Sciatic functional index (SFI) was recorded weekly. Histopathological and ultrastructural evaluations were made using light and electron microscopes, respectively. Sciatic nerve tissue malondialdehyde (MDA), superoxide dismutase (SOD) and tumor necrosis factor-alpha (TNF-α) levels were measured. Gastrocnemius muscle weight was determined. KEY FINDINGS: Carnosine at the doses of 20 and 40 mg/kg accelerated SFI recovery. Wallerian degeneration severity and myelinated fibers density, myelin sheath thickness and diameter as well as ultrastructural changes of myelinated axons were improved. It also recovered nerve tissue biochemical (MDA, SOD and TNF-α) changes induced by crush injury. Muscle weight ratio was reached to near normal values. Our results suggest a regenerative effect of carnosine. Inhibition of oxidative stress and inflammatory pathways, along with provocation of myelination and prevention of muscular atrophy might be involved in this effect of carnosine. SIGNIFICANCE: Carnosine treatment might be considered as a therapeutic agent for peripheral nerve regeneration and its functional recovery.

The effects of safranal, a constitute of saffron, and metformin on spatial learning and memory impairments in type-1 diabetic rats: behavioral and hippocampal histopathological and biochemical evaluations.

Safranal is one of saffron constituents and has antioxidant and neuroprotective properties. Metformin is used as an anti-diabetic drug. This study was planned to investigate the separate and combined treatment effects of safranal and metformin on diabetes-induced learning and memory impairments by behavioral and hippocampal histopathological and biochemical evaluations. Diabetes was induced by intraperitoneal injection of streptozotocin (STZ), treatments with safranal (0.025, 0.1 and 0.4 mg/kg), metformin (50 and 200 mg/kg), and a combination of low doses of this chemicals were initiated after confirmation of diabetes and continued for 37 days. Blood glucose concentration was measured before and on days 15, 25 and 35 after injection of streptozotocin. Learning and memory tested using Morris Water Maze (MWM) on days 40-45 and on day 45 hippocampal specimens were collected for determination of malodialdehyde (MDA), tumor necrosis factor-alpha (TNF-α) and Caspase-3 levels and superoxide dismutase (SOD) activity. The hippocampus was also designed for light microscopy evaluation. Hyperglycemia, spatial learning and memory impairments, hippocampal neuron loss, increase of hippocampal MDA, TNF-α and caspase-3 levels and decrease of SOD activity were observed in diabetic rats. Safranal (0.1 and 0.4 mg/kg), metformin (200 mg/kg) and safranal (0.025 mg/kg) with metformin (50 mg/kg) improved the above-mentioned behavioral, histopathological and biochemical changes. Safranal and metformin and their combination improved learning and memory impairments in STZ-induced diabetic rats. Antioxidant, anti-inflammatory and antiapoptotic mechanisms might be involved. It is recommended that safranal be considered for diabetes management.

Ventrolateral orbital cortex oxytocin attenuates neuropathic pain through periaqueductal gray opioid receptor.

BACKGROUND: Oxytocin plays an important role in supraspinal modulation of pain. In the present study, we investigated the effects of ventrolateral orbital cortex (VLOC) microinjection of oxytocin on neuropathic pain after blockade of opioid receptors in this area and ventrolateral periaqueductal gray (vlPAG). METHODS: Neuropathic pain was induced by complete transcection of preoneal and tibial branches of sciatic nerve. The VLOC and vlPAG were unilaterally (contralateral to the sciatic nerve-injured side) and bilaterally implanted with guide cannulas, respectively. Mechanical paw withdrawal threshold (PWT) was measured using von Frey filaments. Area under curve (AUC) was also calculated. RESULTS: Microinjection of oxytocin (5, 10 and 20 ng/site) into the VLOC increased PWT. Antiallodynia induced by oxytocin (20 ng/site) was inhibited by prior intra-VLOC administration of atosiban (an oxytocin receptor antagonist, 100 ng/site) and naloxone (an opioid receptor antagonist, 500 ng/site). Prior microinjection of naloxone (500 ng/site) into the vlPAG also inhibited antiallodynia induced by intra-VLOC microinjection of oxytocin (20 ng/site). All the VLOC and vlPAG microinjected drugs did not alter locomotor activity. CONCLUSIONS: It is concluded that oxytocin and its receptor may be involved in modulation of neuropathic pain at the VLOC level. Opioid receptors of VLOC and vlPAG might be involved in the antiallodynic effect of the VLOC-microinjected oxytocin.