Endocrine Aspects of Pain Pathophysiology: Focus on Adipose Tissue.

BACKGROUND: Multiple factors, including neurobiological, hormonal, psychological, and social/cultural norms, influence the manner in which individuals experience pain. Adipose tissue, once considered solely an energy storage site, has been recognized as a significant endocrine organ that produces and releases a range of hormones and cytokines. In recent years, research has highlighted the role of adipose tissue and its endocrine factors in the pathophysiology of pain. SUMMARY: This narrative review aimed to provide a comprehensive overview of the current knowledge on the endocrine aspects of pain pathophysiology, with a specific focus on adipose tissue. We examine the role of adipokines released by adipose tissue, such as leptin, adiponectin, resistin, visfatin, asprosin in pain perception and response. We also explore the clinical implications of these findings, including the potential for personalized pain management based on endocrine factors and adipose tissue. KEY MESSAGES: Overall, given this background, this review intended to highlight the importance of understanding the endocrine aspects of pain pathophysiology, particularly focusing on the role of adipose tissue, in the development of chronic pain and adipokines. Better understanding the role of adipokines in pain modulation might have therapeutic implications by providing novel targets for addressing underlying mechanism rather than directly focusing on symptoms for chronic pain, particularly in obese individuals.

Cerebrolysin provides effective protection on high glucose-induced neuropathy in cultured rat dorsal root ganglion neurons.

Cerebrolysin, an endogenous peptide with neuroprotective and neurotrophic properties, indicated to be beneficial on diabetic neuropathy by preliminary clinical and experimental studies but without evidence on central or peripheral action. Dorsal root ganglion (DRG) neurons, based on involvement of pain sensation in both health and disease as first relay centers for transmission and processing of peripheral nociceptive sensory signals, was used to investigate possible effects of Cerebrolysin on high glucose-induced neuropathy, as model. DRG's were obtained from adult rats and the isolated neurons were seeded on E-Plate®'s equipped with gold microelectrodes, and incubated in culture media in a CO2 incubator at 37 C. DRGs were exposed to high glucose (50 mM) in the absence and presence of different concentrations of Cerebrolysin ® (2-40 mg/ml). Cell index (derived from cell viability and neurite outgrowth) was recorded with Real-Time Cell Analyzer and was used as primary outcome measure. High glucose-induced cellular neuropathy and neuroprotective effects of Cerebrolysin was evaluated from area under the curve (AUC) of cell index-time graphs. Exposure of DRG neurons to high glucose caused a rapid and persistent decrease in the mean AUC values compared to normoglycemic controls. Co-treatment with Cerebrolysin (40 mg/ml) attenuated this high glucose-induced effect in a concentration-dependent manner. In normoglycemic conditions, treatment with Cerebrolysin caused a dose-dependent increase in the mean AUC values. Cerebrolysin treatment resulted in maintenance of the functional integrity, survival, and promotion of neurite outgrowth of the cultured DRG neurons exposed to high glucose, indicating involvement of peripheral sensory neurons.

Cortexin® Ameliorates High Glucose-Induced Neuropathy in Cultured Rat Sensory Neurons.

INTRODUCTION: The aim of this study was to investigate whether Cortexin®, a brain peptide-containing agent, has any mitigating effect on high glucose-induced neuropathy, using primary cultured rat sensory neurons. MATERIALS AND METHODS: Dorsal root ganglia (DRG) were excised from decapitated adult rats. Individual neurons were isolated following enzymatic and mechanical procedures. Cells were seeded on E-plate® with gold microelectrodes and maintained in conventional culture media in a CO2 incubator at 37°C. After allowing for 24 h for cell adhesion and recovery from acute enzymatic trauma, neurons were exposed to high glucose (HpG) in the absence and presence of different concentrations of Cortexin® (2-40 µg/mL). Neuroprotective effects were followed with the Real-Time Cell Analyzer® by utilizing measurement of Cell Index, a parameter representing cell viability, cell attachment, and neurite outgrowth. RESULTS: Exposure of DRGs to HpG (50 mm) caused a rapid and sustained decrease in the mean area under the curve (AUC, values derived from time vs. Cell Index curve) compared to the mean AUC values in normoglycemic (NG) wells. Co-treatment with Cortexin® attenuated this HpG-induced effect, in a concentration-dependent manner (NG: 1.00 ± 0.00 vs. HG: 0.18 ± 0.02, p < 0.05; and HpG + Cortexin® [40 µg/mL]: 0.66 ± 0.17, p = 0.002 versus HpG). In normoglycemic conditions, Cortexin® treatment led to a concentration-dependent increase in the mean AUC values. CONCLUSIONS: Data from this in vitro study suggest that Cortexin® has potential neuroprotective effects against chronic hyperglycemic insult in rat sensory neurons. Our results warrant further in vivo studies and may have clinical implications for diabetes-associated peripheral neuropathy.

M3 Receptor Pathway Stimulates Rapid Transcription of the CB1 Receptor Activation through Calcium Signalling and the CNR1 Gene Promoter.

In this study, we have investigated a possible mechanism that enables CB1/M3 receptor cross-talk, using SH-SY5Y cells as a model system. Our results show that M3 receptor activation initiates signaling that rapidly upregulates the CNR1 gene, resulting in a greatly potentiated CB1 receptor response to agonists. Calcium homeostasis plays an essential intermediary role in this functional CB1/M3 receptor cross-talk. We show that M3 receptor-triggered calcium release greatly increases CB1 receptor expression via both transcriptional and translational activity, by enhancing CNR1 promoter activity. The co-expression of M3 and CB1 receptors in brain areas such as the nucleus accumbens and amygdala support the hypothesis that the altered synaptic plasticity observed after exposure to cannabinoids involves cross-talk with the M3 receptor subtype. In this context, M3 receptors and their interaction with the cannabinoid system at the transcriptional level represent a potential pharmacogenomic target not only for the develop of new drugs for addressing addiction and tolerance. but also to understand the mechanisms underpinning response stratification to cannabinoids.

Crosstalk between kisspeptin and gonadotropin-inhibitory hormone in the silence of puberty: preclinical evidence from a calcium signaling study.

Kisspeptin and gonadotropin-inhibitory hormone (GnIH) are among suggested neuroendocrine modulators of reproductive function. Intracellular calcium signaling is a critical component in the regulation of a variety of physiological and pathological processes including neurotransmitter release, and, therefore, can be used as signaling indicator for investigating the involvement of kisspeptin, GnIH, and gonadotropin-releasing hormone (GnRH) release. Hence, this study investigated the effects of kisspeptin and GnIH on calcium signaling using immortalized hypothalamic cells (rHypoE-8) as a model. Kisspeptin neurons were loaded with the ratiometric calcium dye (Fura-2 AM, 1 µmol) and intracellular free calcium ([Ca2+]i) responses were quantified using digital fluorescence imaging system. Kisspeptin-10 (100, 300, and 1000 nM) caused a significant increase in [Ca2+]i in rHypoE-8 cells (n = 58, n = 64, and n = 49, respectively, p < 0.001). The kisspeptin receptor antagonist, P234, inhibited the calcium responses to kisspeptin (p < 0.001, n = 32). GnIH (100 and 1000 nM), alone, did not cause any significant change in the mean basal [Ca2+]i levels in kisspeptin cells, but GnIH attenuated the kisspeptin-evoked [Ca2+]i transients (n = 47, p < 0.001). This novel findings of [Ca2+]i signaling in in vitro setting implicate that kisspeptin and GnIH may exert their effects on hypothalamus-pituitary-gonadal (HPG) axis by modulating kisspeptin neurons. These results also implicate that kisspeptin neurons may have an autocrine regulation.

Investigation of Effects of Gadolinium-Based Contrast Agents on Uterine Contractility Using Isolated Rat Myometrium.

BACKGROUND: Despite concerns about safety, gadolinium-based contrast agents (GBCAs) are still used for abdominal and pelvic imaging during pregnancy. Researchers have mainly focused on teratogenicity, while very little is known about their possible direct effects on uterine contractility, yet free gadolinium potentially impacts contractility through interaction with calcium channels. PURPOSE: To investigate possible effects of selected GBCAs (namely gadoteridol, gadoversetamide, gadobutrol, gadoterate meglumine, and gadoxetic acid) on the contractility of rat myometrium. STUDY TYPE: In vitro organ bath study. ANIMAL MODEL: Myometria were isolated from adult (10-12 weeks old) Sprague Dawley rats, both pregnant (N = 8) and nonpregnant (N = 36). FIELD STRENGTH/SEQUENCE: NA. ASSESSMENT: Myometrial strips were suspended in tissue bath containing physiological saline and isometric contractions were recorded. GBCAs were added to the tissue bath cumulatively, and their effects on contractility parameters (quantified by amplitude, frequency, and area under contractility curve [AUC]) were evaluated by 10-minute intervals. STATISTICAL TESTS: Normality data, checked by Shapiro-Wilk test, were transformed by arcsine when needed. One- or two-way analysis of variance was performed, where appropriate, followed by Student-Newman-Keuls test. A P value of <0.05 was considered statistically significant. RESULTS: All of the assayed GBCAs elicited some alterations in the myometrial contractility in a concentration-dependent manner. Gadoterate meglumine, gadoxetic acid, and gadoversetamide caused a concentration-dependent significant attenuation in AUC (oxytocin-induced, from 100% during control period to 45.1 ± 9.0% (nonpregnant) and 59.9 ± 8.5% (pregnant), for 90 µM gadoterate meglumine; respectively), and frequency of the spontaneous and oxytocin-induced contractions. Gadobutrol and gadoteridol at highest dose significantly attenuated mean AUC and frequency of oxytocin-induced contractions of nonpregnant myometrium. DATA CONCLUSION: Results from this in vitro study indicate that GBCAs elicit modulation of myometrial contractions at clinically relevant concentrations. These effects may account, at least partially, for the known potential side effects (rare cases of miscarriages and elective abortion) of these agents. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY: Stage 5.

An in vitro Study on the Contractility of Epileptic Myometrium and Effects of Antiepileptic Agents on Oxytocin-Induced Contractions of Myometrium Isolated from Absence Epileptic WAG/Rij Rats.

BACKGROUND/AIMS: The aim of this study was to determine whether spontaneous and stimulated contractile activity of myometrium in epileptic rats is different from healthy ones, and whether antiepileptic drugs (AEDs) have any direct influence on myometrial contractility. METHODS: Myometrial strips from nonpregnant and pregnant adult epileptic WAG/Rij and Wistar rats were suspended in organ bath containing physiological salt solution (37°C and pH 7.4, aerated with 95% oxygen-5% CO2), and isometric contractions were recorded. Effects of cumulative concentrations of selected AEDs including phenytoin, levetiracetam, and valproic acid alone and in combination on oxytocin-induced contractions was examined. Contractile parameters assessed included the area under curve, amplitude, and frequency of contractions, evaluated by 10-min periods. Data were analyzed using one-way analysis of variance and Tukey HSD test. RESULTS: Spontaneous myometrial contractility and responses to oxytocin showed species difference. Compared with that of control Wistar rats, spontaneous contractions of myometrium from nonpregnant epileptic WAG/Rij rats were significantly higher while being significantly lower in pregnant preparations. Upon stimulation with oxytocin, WAG/Rij myometrium showed significantly lower contractile response compared with preparations from healthy control Wistars (p < 0.01). Phenytoin and valproate caused concentration-dependent significant attenuation (p < 0.05) of spontaneous and oxytocin-induced contractions of myometrium from WAG/Rij and Wistar rats, both nonpregnant and pregnant. CONCLUSION: Myometrial smooth muscle from epileptic rats showed different spontaneous and oxytocin-induced contractility, and AEDs showed contractile modulatory actions, phenytoin being the most and levetiracetam the least effective. Although in vitro, our findings may be of clinical implications with regard to obstetric complications in epileptics and use of AEDs during pregnancy, and warrants further investigations.

Kisspeptin leads to calcium signaling in cultured rat dorsal root ganglion neurons.

Although kisspeptin and GPR54 have been reported to be expressed in the neurons of the dorsal root ganglion (DRG) of rats, and kisspeptin has been suggested to be involved in pain modulation in rodents, there is no study on the effects and mechanisms of kisspeptin on sensory neurons. Therefore, the aim of this study was to investigate the effects and mechanism of kisspeptin on intracellular free calcium levels in cultured rat DRG neurons. Bath application of kisspeptin-10 increased intracellular free calcium levels ([Ca2+]i). In the absence of extracellular calcium, the kisspeptin induced an attenuated but still significant increase in [Ca2+]i. [Ca2+]i responses persisted in the presence of protein kinase C (PKC) inhibitor. Data from this study revealed that kisspeptin-10 activates [Ca2+]i signaling independent of PKC in cultured rat sensory neurons suggesting that peripheral site is also involved in the pain modulating effect of kisspeptin.

Agomelatine modulates calcium signaling through protein kinase C and phospholipase C-mediated mechanisms in rat sensory neurons.

Agomelatine, a novel antidepressant exerting its effects through melatonergic and serotonergic systems, implicated to be effective against pain including neuropathic pain but without any knowledge of mechanism of action. To explore the possible role of agomelatine on nociceptive transmission at the peripheral level, the effects of agomelatine on intracellular calcium ([Ca2+ ]i ) signaling in peripheral neurons were investigated in cultured rat dorsal root ganglion (DRG) neurons. Using the fura-2-based calcium imaging technique, the effects of agomelatine on [Ca2+ ]i and roles of the second messenger-mediated pathways were assessed. Agomelatine caused [Ca2+ ]i signaling in a dose-dependent manner when tested at 10 and 100 µM concentration. Luzindole, a selective melatonin receptor antagonist, almost completely blocked the agomelatine-induced calcium signals. The agomelatine-induced calcium transients were also nearly abolished following pretreatment with the 100 ng/ml pertussis toxin, a Gi/o protein inhibitor. The stimulatory effects of agomelatine on [Ca2+ ]i transients were significantly reduced by applications of phospholipase C (PLC) and protein kinase C (PKC) blockers, 10 µM U73122, and 10 µM chelerythrine chloride, respectively. The obtained results of agomelatine-induced [Ca2+ ]i signals indicates that peripheral mechanisms are involved in analgesic effects of agomelatine. These mechanisms seems to involve G-protein-coupled receptor activation and PLC and PKC mediated mechanisms.

A prospective clinical investigation of the effects of anti-TNF alpha therapy on exercise capacity in patients with ankylosing spondylitis

Background/aim: The purpose of this study was to investigate possible effects of anti-TNF alpha therapy on cardiorespiratory fitness and physical functional capacity of patients with ankylosing spondylitis (AS). Materials and methods: Twenty-eight AS patients meeting the modified New York criteria with active disease state and an equivalent number of healthy individuals as the control were prospectively enrolled. Physical working capacity and aerobic exercise capacity of the participants were determined by using cardiopulmonary exercise tests, performed before and 4 months after initiation of anti-TNF alpha therapy. Results: The mean age of the patients was 37 ± 9.1 years, and mean duration of disease was 8.9 ± 7.6 years. Patients with AS exhibited significantly lower aerobic exercise capacity (VO2peak: 21.2 ± 5.5 vs. 27.2 ± 6.6 ml/kg/min, P = 0.001), maximum power output (110.4 ± 34.8 vs.153 ± 39.8 W, P = 0.0001), and exercise duration (16.3 ± 2.6 vs. 19.6 ± 2.9 min, P = 0.0001) than the healthy controls. When patients were reevaluated after 4 months of anti-TNF alpha therapy, significant improvement was obtained in patients' aerobic capacity, maximum power output, and exercise duration. Conclusions: Results from this study indicate that in addition to inflammatory parameters and quality of life index, even short-term anti-TNF alpha therapy results in significant improvement in cardiopulmonary health status as objectively reflected by peak VO2,maximum work rate, and exercise duration.

Does pain sensitivity increase during ictal period? Evidence from absence epileptic WAG/Rij rats.

OBJECTIVE: The hyperexcitable brain provides a common ground for comorbidity of pain syndromes and epilepsy. There are controversial reports about pain sensitivity during the ictal period. We analyzed the pain sensitivity during the ictal period in the genetic absence epilepsy animal model, Wistar Albino Glaxo/Rijswijk (WAG/Rij) rats. METHODS: The ictal and interictal pain sensitivities of symptomatic WAG/Rij rats (8 months old, n = 19) were determined and compared with those of age-matched control Wistar rats (n = 19). Pain sensitivity was assessed by applying heat stimulation to hind paws and measuring the paw-withdrawal latency using a thermal plantar analgesia meter in awake and freely moving animals. All measurements were made during the interictal and ictal periods and confirmed by simultaneous electroencephalography (EEG) through intracranially implanted electrodes. RESULTS: The nociceptive stimulus-induced withdrawal latency during the ictal period in absence epilepsy WAG/Rij rats was significantly shorter when compared with that during the interictal period (p = 0.007) and when compared with that in the control Wistar rats (p = 0.001). CONCLUSION: Our data indicate higher pain sensitivity during the ictal period in absence epilepsy rats. Considering the fact that subjects are less responsive during spike-wave discharges, there is a decrease in the level of consciousness and/or responsiveness ictally during all generalized genetic seizures, this increased pain sensitivity is rather surprising during the ictal period. Although the mechanism remains unknown, this novel finding deserves further investigation.

Kisspeptin increases intracellular calcium concentration by protein kinase C-mediated signaling in the primary cultured neurons from rat hippocampus.

In addition to the fact that kisspeptin and its receptor GPR54 are well known to be abundantly expressed in the hypothalamus with suggestive roles in the initiation of puberty and similar reproductive system properties, there is also proof showing that kisspeptin might have influences on hippocampal functions. In our previous study, it was shown that kisspeptin increased free intracellular Ca2+ values ([Ca2+]i) through protein kinase C (PKC) activation in GT1-7 cells. For this reason, we examined the influences of kisspeptin on [Ca2+]i in hippocampal neurons to determine if kisspeptin shows its effects on hippocampus through the same mechanism. Hippocampal neurons were excised from the brains of fetuses on 17th embryonic day from maternal rats. The influences of kisspeptin on [Ca2+]i in hippocampal neurons were examined through in vitro calcium imaging system. The responses of [Ca2+]i to kisspeptin were quantified by the changes in 340nm/380nm ratio.  Kisspeptin-10 caused [Ca2+]i transients in hippocampal neurons. The change in [Ca2+]i by 100 nM kisspeptin was prevented by pre-treating the cells in PKC inhibitor chelerythrine chloride. According to the results, kisspeptin activates intracellular calcium signaling in hippocampal neurons via the pathway that depends on PKC. The results of this study suggest that kisspeptin may have a role in hippocampal neuron functions.

Epilepsy may cause increased pain sensitivity: Evidence from absence epileptic WAG/Rij rats.

OBJECTIVE: The comorbidity of epilepsy and pain disorders as well as effectiveness of certain therapeutic approaches in both conditions attracted attention to epilepsy-pain interactions. This lead to the discovery of significantly shared pathophysiological mechanisms although many aspects remain largely unknown. To test the hypothesis that epilepsy may be associated with altered pain sensitivity, we analyzed interictal pain sensitivity using epilepsy prone WAG/Rij rats, a genetic model exhibiting age-related-onset absence epilepsy. METHODS: Two series of experiments were conducted. In experiment I, pain sensitivity of symptomatic WAG/Rij rats were compared with age-matched control Wistar rats. In experiment II, pain sensitivity of WAG/Rij rats were monitored longitudinally when they were presymptomatic (at 2months) and symptomatic (after maturation, at 8months), and compared with age-matched control Wistar rats. Pain sensitivity was assessed by applying heat stimuli to hind paws and measuring the paw-withdrawal latency using thermal plantar analgesia meter in awake and freely moving animals. All pain measurements were made during the interictal period, confirmed by simultaneous electroencephalography through intracranially implanted electrodes. RESULTS: In experiment I, the interictal pain withdrawal latency of symptomatic WAG/Rij rats was significantly shorter than control Wistar rats (P<0.01). In experiment II, WAG/Rij rats had significantly shorter latency of withdrawal response than control Wistar rats, both at presymptomatic (P<0.05) and symptomatic stage (P<0.0001). Matured (8months old) control Wistar rats demonstrated significantly increased withdrawal latency compared to the 2months animals (P<0.01), but the WAG/Rij rats did not (P>0.5). CONCLUSION: Epileptic WAG/Rij rats present significantly increased pain sensitivity when compared to control Wistar rats, suggesting comorbidity of epilepsy and pain.

Effects of alpha-lipoic acid on retinal ganglion cells, retinal thicknesses, and VEGF production in an experimental model of diabetes.

PURPOSE: The purpose of the present study was to investigate the effect of alpha-lipoic acid (ALA) on the thicknesses of various retinal layers and on the numbers of retinal ganglion cells and vascular endothelial growth factor levels in experimental diabetic mouse retinas. METHODS: Twenty-one male BALB/C mice were made diabetic by the intraperitoneal administration of streptozotocin (200 mg/kg). One week after the induction of diabetes, the mice were divided randomly into three groups: control group (non-diabetic mice treated with alpha-lipoic acid, n = 7), diabetic group (diabetic mice without treatment, n = 7), and alpha-lipoic acid treatment group (diabetic mice with alpha-lipoic acid treatment, n = 7). At the end of the 8th week, the thicknesses of the inner nuclear layer (INL), outer nuclear layer (ONL), and full-length retina were measured; also retinal ganglion cells and VEGF expressions were counted on the histological sections of the mouse retinas and compared with each other. RESULTS: The thicknesses of the full-length retina, ONL, and INL were significantly reduced in the diabetic group compared to the control and ALA treatment groups (p = 0.001), whereas the thicknesses of these layers did not show a significant difference between ALA treatment and control groups. The number of ganglion cells in the diabetic group was significantly lower than those in the control and ALA treatment groups (p = 0.001). The VEGF expression was significantly higher in the diabetic group and mostly observed in the ganglion cell and inner nuclear layers compared to the control and ALA treatment groups (p = 0.001). Therefore, the number of ganglion cells and VEGF levels did not show significant differences between the ALA treatment and control groups (p = 0.7). CONCLUSIONS: Our results show that alpha-lipoic acid treatment may have an impact on reducing VEGF levels, protecting ganglion cells, and preserving the thicknesses of the inner and outer layers in diabetic mouse retinas.

Effects of apelin-13 in mice model of experimental pain and peripheral nociceptive signaling in rat sensory neurons.

OBJECTIVE: Apelin-13 is an endogenous peptide with potential analgesic action, although the sites of its analgesic effects remain uncertain and the results are even controversial with regard to its pain modulating action. This study evaluated the possible pain-modulating action of peripherally administered apelin-13 using heat-induced, withdrawal latency to the thermal stimuli, acute pain model in mice. Involvement of peripheral mechanisms was tested, by using the intracellular calcium concentrations as a key signal for nociceptive transmission, in cultured rat dorsal root ganglion (DRG) neurons. METHODS: DRG neurons were cultured on glass coverslips following enzymatic digestion and mechanical agitation, and loaded with the calcium-sensitive dye Fura-2 acetoxymethyl ester (1 µM). Intracellular calcium responses in individual DRG neurons were quantified by ratiometric calcium imaging technique. RESULTS: Peripheral injection of a single dose of apelin-13 (100 mg/kg and 300 mg/kg) significantly decreases the latency to painful stimuli in a dose and time-dependent manner (p < 0.01, p < 0.05, respectively, n = 8 each). Apelin-13 (0.1 µM and 1 µM) did not produce a significant effect on cytoplasmic Ca(2+) ([Ca(2+)](i)) responses, evoked by membrane depolarization, in cultured rat DRG neurons. CONCLUSION: Together these results indicate that apelin-13 can cause increased pain sensitivity after peripheral administration, but this effect does not involve calcium mediated signaling in primary sensory neurons.

Spinorphin inhibits membrane depolarization- and capsaicin-induced intracellular calcium signals in rat primary nociceptive dorsal root ganglion neurons in culture.

OBJECTIVE: Spinorphin is a potential endogenous antinociceptive agent although the mechanism(s) of its analgesic effect remain unknown. We conducted this study to investigate, by considering intracellular calcium concentrations as a key signal for nociceptive transmission, the effects of spinorphin on cytoplasmic Ca(2+) ([Ca(2+)]i) transients, evoked by high-K(+) (30 mM) depolariasation or capsaicin, and to determine whether there were any differences in the effects of spinorphin among subpopulation of cultured rat dorsal root ganglion (DRG) neurons. METHODS: DRG neurons were cultured on glass coverslips following enzymatic digestion and mechanical agitation, and loaded with the calcium sensitive dye fura-2 AM (1 µM). Intracellular calcium responses in individual DRG neurons were quantified using standard fura-2 based ratiometric calcium imaging technique. All data were analyzed by using unpaired t test, p < 0.05 defining statistical significance. RESULTS: Here we found that spinorphin inhibited cytoplasmic Ca(2+) ([Ca(2+)]i) transients, evoked by depolarization and capsaicin selectively in medium and small cultured rat DRG neurons. Spinorphin (10-300 µM) inhibited the Ca(2+) signals in concentration dependant manner in small- and medium diameter DRG neurons. Capsaicin produced [Ca(2+)]i responses only in small- and medium-sized DRG neurons, and pre-treatment with spinorphin significantly attenuated these [Ca(2+)]i responses. CONCLUSION: Results from this study indicates that spinorphin significantly inhibits [Ca(2+)]i signaling, which are key for the modulation of cell membrane excitability and neurotransmitter release, preferably in nociceptive subtypes of this primary sensory neurons suggesting that peripheral site is involved in the pain modulating effect of this endogenous agent.

Effects of two antioxidants; α-lipoic acid and fisetin against diabetic cataract in mice.

The purpose of this study was to determine whether α-lipoic acid and fisetin have protective effects against cataract in a streptozotocin-induced experimental cataract model. Twenty-eight male BALB/C mice were made diabetic by the intraperitoneal administration of streptozotocin (200 mg/kg). Three weeks after induction of diabetes, mice were divided randomly into 4 groups in which each group contained 7 mice; fisetin-treated group (group 1), α-lipoic acid-treated group (group 2), fisetin placebo group (group 3), α-lipoic acid placebo group (group 4). Fisetin and α-lipoic acid were administered intraperitoneally weekly for 5 weeks. Cataract development was assessed at the end of 8 weeks by slit lamp examination, and cataract formation was graded using a scale. All groups developed at least grade 1 cataract formation. In the fisetin-treated group, the cataract stages were significantly lower than in the placebo group (p = 0.02). In the α-lipoic acid-treated group, the cataract stages were lower than in the placebo group but it did not reach to a significant value. Both fisetin and α-lipoic acid had a protective effect on cataract development in a streptozotocin-induced experimental cataract model. The protective effect of fisetin appears as though more effective than α-lipoic acid.

Investigation of the effects of different processing methods on the selected nutritional properties of pumpkin and determining the appropriate process for pumpkin yogurt.

The processing methods, especially cooking, can cause quality losses, particularly in the nutritional value of the fresh product. This study investigated the effects of preprocessing methods on the nutritional properties of pumpkin and the physicochemical and sensory properties of pumpkin yogurt. Two different pumpkin varieties (Cucurbita pepo and Cucurbita maxima) were subjected to three different preprocessing methods (freeze-drying, boiling, and baking). Boiling significantly increased antioxidant activity (p ≤ .05), followed by baking. C. maxima had higher TDF and TPC than C. pepo, but in both pumpkin varieties, TDF did not change with heat treatment (boiling and baking), while TPC decreased. Mineral contents remained the same or decreased with heat treatment, except for Mn and Fe. In particular, the addition of C. maxima significantly affected the color parameters (L*, a*, b*) of yogurt and improved WHC (from 68.9% to 91.6%) and hardness (from 58.0 to 193.5 g; p ≤ .05). The sensory evaluation concluded that heat-treated (boiled and baked) samples were preferred more than freeze-dried raw ones. In conclusion, the results revealed that adding boiled and baked pumpkins, especially the preference for C. maxima instead of C. pepo, improved the quality parameters of yogurt.

Coagulation temperature and smoking time determine product quality and shelf life of the acid-heat coagulated Circassian cheese.

This study examined the effects of process parameters on acid-heat coagulated Circassian cheese. For this purpose, cheeses were produced at coagulation temperatures of 70°C and 90°C, and smoked for 0, 2.5, and 6 h in both summer and winter. Microbiological, textural, proteolytic, and sensorial changes were observed for 90 days at 30-day intervals. According to the results, coagulation at 90°C instead of 70°C formed a firmer structure. Six-hour smoking time instead of 2.5-h provided higher dry matter, reduced proteolysis rates, and extended the microbial shelf life. In addition, higher (6 h) smoking decelerated sourness while resulting in intense smoke flavor and higher lipolytic activity. In conclusion, seasonal changes in milk and applied the process conditions revealed significant differences in the quality parameters and shelf life of acid-heat coagulated Circassian cheese.

Anti-TNF-α therapy may not improve arterial stiffness in patients with AS: a 24-week follow-up.

OBJECTIVE: The availability of new-generation drugs has provided significant success reflected by disease activity markers and clinical status in AS, but controversial reports necessitate further assessment of associated increased risk of cardiovascular burden that might persist. Hence this prospective clinical study evaluated the effectiveness of a 24-week anti-TNF-α therapy on vascular stiffness [pulse wave velocity (PWV)] in AS. METHODS: A total of 28 active AS patients (21 males, 7 females) were enrolled before the start of biologic therapy. Demographic and clinical characteristics were recorded. Arterial stiffness was assessed using PWV. Patients were evaluated before and 24 weeks after anti-TNF-α therapy. RESULTS: The mean disease duration was 8.4 (4.9) years. After 24 weeks of anti-TNF-α therapy, despite significant improvements in patients' symptoms and clinical activity parameters, including BASDAI score [4.9 (0.9) vs 1.9 (0.5), P = 0.0001], ESR [35.5 (23.1) vs 13.8 (9.2) mm/h, P = 0.0001) and CRP level [2.1 (1.6) vs 0.4 (0.3) ng/dl, P = 0.0001], no significant change was seen in arterial stiffness parameters [7.9 (1.3) vs 7.7 (1.3) m/s, P = 0.412]. Significant correlation was determined between arterial stiffness and age, systolic blood pressure and high-density lipoprotein cholesterol levels. CONCLUSION: Despite significant improvement in markers of disease activity, anti-TNF-α therapy does not seem to improve arterial stiffness, a significant AS-associated cardiovascular burden. Thus, when treating AS, significant end-points other than DASs should also be considered, and any hidden threat like arterial stiffness should be addressed further.