Complete essential oils of Laurus nobilisinducing antinociceptiveaction by opioid mechanism in C-Reflex and spinal Wind-Up model in rat / Aceites esenciales totales de Laurus nobilis inducen acción antinociceptivamediante mecanismo opioide en el modelode Reflejo-C y Wind-Up espinal en ratas

The essential oil of Laurus nobilis L. was used to test their antinociceptive efficacy. It was applied intraperitoneally (i.p.) to rats subjected to a nociception test (C reflex and spinal wind-up). The results showed that the essential oil applied at higher doses (0.06 mg/Kg) causes a complete abolition of the spinal wind-up, while the C reflex was unchanged, indicating a clear antinociceptive effect. At lower concentrations (0.012 mg/Kg), there was a lowering in the wind-up by 85% within ten minutes of the essential i.p. oil application. Interestingly, there was an effect of naloxone (0.08 mg/Kg i.p.) When applied, a change occurs that almost entirely reversed the antinociception caused by the essential oil from Laurus nobilis. We conclude that there is a significant antinociceptive effect of the essential oil of Laurus nobilis subjected to electric nociception. In addition, it was observed that naloxone reversed the antinociceptive effect (wind-up) produced by Laurus nobilis.

El aceite esencial de Laurus nobilis L. se usó para probar su eficacia antinociceptiva. Se aplicó por vía intraperitoneal (i.p.) a ratas sometidas a una prueba de nocicepción (reflejo-C y wind-up espinal). Los resultados mostraron que el aceite esencial aplicado a dosis más altas (0.06 mg/Kg) abolió completamente el wind-up espinal, mientras que el reflejo-C no cambió, lo que indica un claro efecto antinociceptivo. A concentraciones más bajas (0.012 mg/Kg), hubo una disminución en el wind-up en un 85% dentro de los diez minutos del i.p. la aplicación del aceite esencial. Curiosamente, hubo un efecto de la naloxona (0.08 mg/Kg i.p.) la cual revierte casi por completo la antinocicepción causada por el aceite esencial de Laurus nobilis. Concluimos que existe un efecto antinociceptivo significativo del aceite esencial de Laurus nobilis sometido a nocicepción eléctrica. Además, se observó que la naloxona revirtió el efecto antinociceptivo (wind-up) producido por Laurus nobilis.

Comparison of Dexmedetomidine and Remifentanil on Airway Reflex and Hemodynamic Changes during Recovery after Craniotomy

PURPOSE: During emergence from anesthesia for a craniotomy, maintenance of hemodynamic stability and prompt evaluation of neurological status is mandatory. The aim of this prospective, randomized, double-blind study was to compare the effects of dexmedetomidine and remifentanil on airway reflex and hemodynamic change in patients undergoing craniotomy. MATERIALS AND METHODS: Seventy-four patients undergoing clipping of unruptured cerebral aneurysm were recruited. In the dexmedetomidine group, patients were administered dexmedetomidine (0.5 µg/kg) for 5 minutes, while the patients of the remifentanil group were administered remifentanil with an effect site concentration of 1.5 ng/mL until endotracheal extubation. The incidence and severity of cough and hemodynamic variables were measured during the recovery period. Hemodynamic variables, respiration rate, and sedation scale were measured after extubation and in the post-anesthetic care unit (PACU). RESULTS: The incidence of grade 2 and 3 cough at the point of extubation was 62.5% in the dexmedetomidine group and 53.1% in the remifentanil group (p=0.39). Mean arterial pressure (p=0.01) at admission to the PACU and heart rate (p=0.04 and 0.01, respectively) at admission and at 10 minutes in the PACU were significantly lower in the dexmedetomidine group. Respiration rate was significantly lower in the remifentanil group at 2 minutes (p<0.01) and 5 minutes (p<0.01) after extubation. CONCLUSION: We concluded that a single bolus of dexmedetomidine (0.5 µg/kg) and remifentanil infusion have equal effectiveness in attenuating coughing and hemodynamic changes in patients undergoing cerebral aneurysm clipping; however, dexmedetomidine leads to better preservation of respiration.

Effectiveness of hip muscle strengthening in patellofemoral pain syndrome patients: a systematic review

Introduction: Patellofemoral pain syndrome (PFPS) is characterized by anterior knee pain, which may limit the performance of functional activities. The influence of hip joint motion on the development of this syndrome has already been documented in the literature. In this regard, studies have investigated the effectiveness of hip muscle strengthening in patients with PFPS. Objectives: The aims of this systematic review were (1) to summarize the literature related to the effects of hip muscle strengthening on pain intensity, muscle strength, and function in individuals with PFPS and (2) to evaluate the methodological quality of the selected studies. Method: A search for randomized controlled clinical trials was conducted using the following databases: Google Scholar, MEDLINE, PEDro, LILACS, and SciELO. The selected studies had to distinguish the effects of hip muscle strengthening in a group of patients with PFPS, as compared to non-intervention or other kinds of intervention, and had to investigate the following outcomes: pain, muscle strength, and function. The methodological quality of the selected studies was analyzed by means of the PEDro scale. Results: Seven studies were selected. These studies demonstrated that hip muscle strengthening was effective in reducing pain. However, the studies disagreed regarding the treatments' ability to improve muscle strength. Improvement in functional capabilities after hip muscle strengthening was found in five studies. Conclusion: Hip muscle strengthening is effective in reducing the intensity of pain and improving functional capabilities in patients with PFPS, despite the lack of evidence for its ability to increase muscle strength. .

Isolation of compound and CNS depressant activities of Mikania scandens Willd with special emphasis to brain biogenic amines in mice.

Mikania scandens, a twining herb that grows as a weed in India and Bangladesh is used as vegetables and is a good source of vitamin A, C, B complex, mikanin, sesquiterpenes, betasitosterin, stigmasterol and friedelin. The present communication reports CNS depressant activities with special emphasis to brain biogenic amines in mice. Ethanol extract of leaves of M. scandens (EEMS) was prepared by Soxhalation and analyzed chemically. EEMS potentiated sleeping time induced by pentobarbitone, diazepam and meprobamate and showed significant reduction in the number of writhes and stretches. EEMS caused significant protection against pentylene tetrazole-induced convulsion and increased catecholamines and brain amino acids level significantly. Results showed that EEMS produced good CNS depressant effects in mice.

Muscular performance characterization in athletes: a new perspective on isokinetic variables

Background: Isokinetic dynamometry allows the measurement of several variables related to muscular performance, many of which are seldom used, while others are redundantly applied to the characterization of muscle function. Objectives: The present study aimed to establish the particular features of muscle function that are captured by the variables currently included in isokinetic assessment and to determine which variables best represent these features in order to achieve a more objective interpretation of muscular performance. Method: This study included 235 male athletes. They performed isokinetic tests of concentric knee flexion and extension of the dominant leg at a velocity of 60º/s. An exploratory factor analysis was performed. Results: The findings demonstrated that isokinetic variables can characterize more than muscle torque production and pointed to the presence of 5 factors that enabled the characterization of muscular performance according to 5 different domains or constructs. Conclusions: The constructs can be described by torque generation capacity; variation of the torque generation capacity along repetitions; movement deceleration capacity; mechanical/physiological factors of torque generation; and acceleration capacity (torque development). Fewer than eight out of sixteen variables are enough to characterize these five constructs. Our results suggest that these variables and these 5 domains may lead to a more systematic and optimized interpretation of isokinetic assessments. .

Effects of opioids on local anesthesia in the rat: a codeine and tramadol study

Opioids are central analgesics that act on the CNS (central nervous system) and PNS (peripheral nervous system). We investigated the effects of codeine (COD) and tramadol (TRAM) on local anesthesia of the sciatic nerve. Eighty Wistar male rats received the following SC injections in the popliteal fossa: local anesthetic with epinephrine (LA); local anesthetic without vasoconstrictor (LA WV); COD; TRAM; LA + COD; LA + TRAM; COD 20 minutes prior to LA (COD 20' + LA) or TRAM 20 minutes prior to LA (TRAM 20' + LA). As a nociceptive function, the blockade was considered the absence of a paw withdraw reflex. As a motor function, it was the absence of claudication. As a proprioceptive function, it was the absence of hopping and tactile responses. All data were compared using repeated-measures analysis of variance (ANOVA). Opioids showed a significant increase in the level of anesthesia, and the blockade duration of LA + COD was greater than that of the remaining groups (p < 0.05). The associated use of opioids improved anesthesia efficacy. This could lead to a new perspective in controlling dental pain.

Central 5-HT2A receptors modulate the vagal bradycardia in response to activation of the von Bezold-Jarisch reflex in anesthetized rats

Activation of 5-hydroxytryptamine (5-HT) 5-HT1A, 5-HT2C, 5-HT3, and 5-HT7 receptors modulates the excitability of cardiac vagal motoneurones, but the precise role of 5-HT2A/2B receptors in these phenomena is unclear. We report here the effects of intracisternal (ic) administration of selective 5-HT2A/2B antagonists on the vagal bradycardia elicited by activation of the von Bezold-Jarisch reflex with phenylbiguanide. The experiments were performed on urethane-anesthetized male Wistar rats (250-270 g, N = 7-9 per group). The animals were placed in a stereotaxic frame and their atlanto-occipital membrane was exposed to allow ic injections. The rats received atenolol (1 mg/kg, iv) to block the sympathetic component of the reflex bradycardia; 20-min later, the cardiopulmonary reflex was induced with phenylbiguanide (15 µg/kg, iv) injected at 15-min intervals until 3 similar bradycardias were obtained. Ten minutes after the last pre-drug bradycardia, R-96544 (a 5-HT2A antagonist; 0.1 µmol/kg), SB-204741 (a 5-HT2B antagonist; 0.1 µmol/kg) or vehicle was injected ic. The subsequent iv injections of phenylbiguanide were administered 5, 20, 35, and 50 min after the ic injection. The selective 5-HT2A receptor antagonism attenuated the vagal bradycardia and hypotension, with maximal effect at 35 min after the antagonist (pre-drug = -200 ± 11 bpm and -42 ± 3 mmHg; at 35 min = -84 ± 10 bpm and -33 ± 2 mmHg; P < 0.05). Neither the 5-HT2B receptor antagonists nor the vehicle changed the reflex. These data suggest that central 5-HT2A receptors modulate the central pathways of the parasympathetic component of the von Bezold-Jarisch reflex.

Neonatal exposure to citalopram, a serotonin selective reuptake inhibitor, programs a delay in the reflex ontogeny in rats / Exposição neonatal ao citalopram, um inibidor seletivo da recaptação de serotonina, programa retardo na ontogênese reflexa em ratos

Serotonin influences the growth and development of the nervous system, as well as its behavioral manifestations. The possibility exists that increased brain serotonin availability in young animals modulates their neuro-behavioral responses. This study investigated the body weight gain and reflex ontogeny of neonatal rats treated during the suckling period with two doses of citalopram (5 mg, or 10 mg/kg, sc, daily). The time of the appearance of reflexes (palm grasp righting, free-fall righting, vibrissa placing, auditory startle response, negative geotaxis and cliff avoidance) as well as the body weight evolution were recorded. In general, a delay in the time of reflex development and a reduced weight gain were observed in drug-treated animals. These findings suggest that serotoninergic mechanisms play a role in modulating body weight gain and the maturation of most reflex responses during the perinatal period in rats.

A serotonina influencia o crescimento e o desenvolvimento do sistema nervoso e sua expressão comportamental. O aumento da disponibilidade de serotonina no cérebro de ratos jovens parece modular as respostas neurocomportamentais. Neste estudo, foram investigados o ganho de peso corporal e a ontogênese dos reflexos em ratos neonatos, tratados diariamente, durante o período de aleitamento, com duas doses de citalopram (5 ou 10 mg/Kg de peso corporal, via subcutânea). Foram avaliados, o tempo de aparecimento dos reflexos (preensão palmar, endireitamento, colocação pelas vibrissas, resposta ao susto, geotáxico negativo e aversão ao precipício), e a evolução do peso corporal. Foi observado atraso no tempo de desenvolvimento de alguns reflexos e redução no ganho de peso corporal. Os achados em ratos sugerem que as alterações no ganho de peso corporal e na maturação dos reflexos são programadas, durante o período perinatal, com participação de mecanismos serotoninérgicos de modulação.

role of succinylcholine in the prevention of the obturator nerve reflex during transurethral resection of bladder tumors

To present our 8 year experience in the prevention of the obturator nerve reflex during transurethral resection of bladder tumors. This study was performed in Ataturk University Hospital between 1999 and 2007. We retrospectively reviewed the records of 89 patients with inferolateral bladder tumors, who underwent transurethral resection under epidural or general anesthesia and requested obturator nerve reflex inhibition. Epidural anesthesia was administered to 57 patients, while the remaining 32 patients underwent general anesthesia via mask; and succinylcholine was administered prior to resection. Of the 57 patients received epidural anesthesia, 18 were diagnosed as inferolateral bladder tumors during endoscopy and had to undergo general anesthesia. Obturator nerve block was attempted preoperatively in 39 patients. However, a nerve identification failure, a hematoma, and 4 obturator nerve reflex events, despite the block, were observed and these patients were subjected to general anesthesia with succinylcholine. Fifty-six patients [32 patients initially had general anesthesia and 24 converted from epidural to general anesthesia] were all given succinylcholine prior to resection. Due to its mechanism of action, succinylcholine is completely effective and represents a simple alternative to obturator nerve block. No contraction was observed in any patient given succinylcholine

The Reflex Effects on the Respiratory Regulation of the CO2 at the Different Flow Rate and Concentration

PURPOSE: The purpose of this study was to investigate the activation of the respiratory centers during insufflation of the larynx with CO2 at different flow rates and concentrations. MATERIALS AND METHODS: The experiments were carried out in spontaneous air breathing rabbits, anesthetized with thiopental sodium (25mg kg(-1) i.v.). The larynx was separated from the oropharyngeal cavity and the trachea. The tidal volume (VT) and respiratory frequency (f min(-1)) were recorded from the lower tracheal cannula. The respiratory minute volume (VE) was calculated, the action potentials from the right phrenic nerve were recorded and the inspiratory (TI) and expiratory (TE) periods and the mean inspiratory flow rate (VT/TI) were calculated. The larynx was insufflated at flow rates of 500mL min(-1) and 750mL min(-1), with 7 and 12% CO2-Air by means of a respiratory pump. RESULTS: Insufflation of the larynx, with both gas mixtures, decreased the f and VT significantly. The TI and TE were found to increase significantly due to the decreasing in f. There was a significant decrease in VT/TI ratio. Following bilateral midcervical vagotomy, on the passing of both gas mixtures, significant decreases were observed in the VT, and the responses of f, TI and TE were abolished. After cutting the superior laryngeal nerve, the responses of the VT to both gas mixtures were abolished. CONCLUSION: In conclusion, the results of this study purpose that the stimulation of the laryngeal mechanoreceptors by the effect of hyper- capnia decreases the activation of the respiratory center

Phenyldiguanide activates cardiac receptors to produce responses by involving three different efferent pathways in anaesthetized rats.

The present study was undertaken to determine the afferent and efferent pathways involved in the phenyldiguanide (PDG)-induced reflex response in rats. Intravenous (iv) injection of PDG (10 microg/kg), produced hypotension, bradycardia and apnea over a period of time. Bilateral vagotomy abolished the PDG-induced reflex changes. Atropine (2 mg/kg; iv) blocked only the bradycardiac response produced by PDG, while prazosin (0.5 mg/kg; iv) blocked the hypotensive response, and bilateral vagotomy in these animals abolished the apneic response. In separate series of experiments, intrapericardial injection of lignocaine abolished the hypotensive and bradycardiac responses evoked by PDG in artificially ventilated rats. The results reveal that the PDG-induced reflex is mediated through vagal afferents originating from the heart and efferents involve three different pathways. The bradycardiac response was through the muscarinic receptors, the hypotension is mediated through alpha1 adrenoceptors and the apnea presumably through the spinal motoneurones supplying the respiratory muscles.

Heart rate responses to intravenous serotinin in rats with acute chagasic myocarditis

We administered serotonin to rats with experimentally induced chagasic myocarditis in order to study the Bezold-Jarisch reflex. Sixteen 4-month old Wistar rats were inoculated with 200.000 T. cruzi parasites ("Y"strain). Between days 18 and 21 (acute stage), 8 infected rats and 8 age-matched controls received intravenous serotonin as a bolus injection at the following doses: 0.5, 1.0, 2.0, 4.0, 6.0, 8.0, 10.0, 12,0, and 14.0 mug/kg. Heart rate was recorded before, during and after each dose of serotonin. The remaining 8 infected animals and 8 controls were subjected to the same experimental procedure during the subacute stage, i.e., days 60 to 70 after inoculation. The baseline heart rate of the infected animals studied during the acute stage (327 + 62 beats/min, mean + SD) was higher than that of the controls (248 + 52, P<0.01). The heart rate changes were expressed as percent changes to correct for the higher baseline heart rate of the infected animals. A dose-response curve was constructed for each group of animals. The slope for the acutely infected animals (r = -0.95, b = -3.98) was not different from that for the control animals (r = -0,92, b = -3.50). The infected animals studied during the subacute stage (r = -0.92, b = -4.33) were not different from the age-matched controls (r = -0.87, b = -4.03). These results suggest that the afferent and efferent pathways which mediate the Bezold-Jarisch reflex are functionally preserved in rats with histologically proved chagasic myocarditis.

Exaggerated Bezold-Jarisch reflex in the hypertension induced by inhibition of nitric oxide synthesis

The present study was designed investigate the role of cardio-pulmonary reflex, more specifically the bezold-Jarisch reflex, in experimental hypertension induced by chronic administration of Nw-nitro-L-arginine methyl ester (L-NAME) (0,5 mg/ml) added to the drinking water for 6 days. The study was perfomed in male Wistar rats (200-350 g), 9 animals per group. L-NAME ingestion caused a significant increase in resting mean arterial pressure (MAP: 182 + or - 4mmHg) and heart rate (HR: 447 = or - 20 bpm) when compared to untreated rats (MAP: 112 = or - 3 mmHg and HR: 355 + or - 10 bpm). Cardiopulmonary receptors were chemically stimulated with bolus injections of 5-hydroxytryptamine (5-HT, 4-10 ug/Kg, iv) followed by measuring the falls in diastolic arterial pressure (DAP) and HR in conscious and freely moving animals. An expected, the responses to intravenous injections of 5-HT consisted of a dose-dependent reduction in HR (from 26 = or - 14 to 175 + or - 25 bpm) and DAP (from 7 + or - 4 to 39 + or - 3 mmHg) in the control rats. Both bradycardia and diastolic hypotension were significantly accentuated in the L-NAME animals (approximately 30 per cent). These data suggest that, in contrast to other models of hypertension, in the present one caused by inhibition of nitric oxide synthesis, the Bezold-Jarisch reflex exaggerated. This neural dysfunction could be related to changes in the cardiac vagal effrent or effector

Effects of postnatal methylmalonate administration on neurobehavioral development of rats

Administration of methylmalonic acid in rats has been used as a model for methylmalonicacidemia in humans. Nestling Wistar rats of both sexes received 5 injections daily at 3-h intervals (starting at 7:30 a.m.) of saline or methylmalonic acid (MMA, 10 mg/ml) in a volume of 9 microliters/g body weight per injection subcutaneously in the lumbar region from the 5th to the 9th day of life and 11 microliters/g from day 10 to 14. Growth and neuromotor development were assessed by monitoring the following parameters daily in 54 rats: body weight, ear unfolding, incisor eruption, eye opening, righting, palmar grasp, negative geotaxis, cliff avoidance, free-fall righting and startle reflex. The only statistically significant effects of MMA administration were on the day of appearance of the free-fall righting reflex: MMA, 12.44 +/- 1.55 vs 11.0 +/- 0.39 days for saline control (P < 0.05, by two-way ANOVA) and a significant decrease in weight (P < 0.05, by ANOVA with repeated measures). The results suggest that chronic MMA administration to rats has a selective effect on neuromotor development

Mecanorreceptores cardíacos / Cardiac mechanoreceptors

Utilizou-se a noradrenalina na dose padräo de 2 ug/Kg, medindo-se o fluxo na artéria femoral antes e após o estímulo. A injeçäo foi feita em diversos níveis da aorta, intracardíaca e na veia axilar. Para estudar a dependência do fenômeno com as vias nervosas, estimularam-se cäes com os nervos femoral e ciático seccionados, com desnervaçäo dos seios carotídeos e aórtico e com os vagos seccionados bilateralmente. Foi possível observar que: 1 - O aumento da atividade cardíaca que se acompanha de aumento da contratilidade é estímulo eficaz para desencadear o aumento do fluxo na artéria femoral. O aumento da contratilidade cardíaca e a diminuiçäo da resistência periférica säo proporcionais à dose de noradrenalina injetada (dentro dos limites de 1 a 3 ug). 2- No cäo com uma pata posterior submetida à secçäo dos nervos femoral ciático, a injeçäo de noradrenalina causa diminuiçäo da resistência vascular na pata normal, simultaneamente com o aumento da resistência na pata desnervada. Essa observaçäo demonstra ser esse fenômeno um reflexo. 3- A secçäo dos seios carotídeos e aórticos quase näo influencia essa resposta reflexa. 4- A injeçäo de noradrenalina na artéria femoral e em diversas posiçöes da aorta näo causa diminuiçäo da resistência periférica. A injeçäo endovenosa no bulbo aórtico e intracardíaca (ventrículo esquerdo) sempre leva à vasodilataçäo na regiäo estudada. 5- A secçäo vagal deprime acentuadamente a resposta, demonstrando ser essa a principal via nervosa responsável pelo reflexo

Calcium channel blockers and the CVS reflex responses during lower body suction.

Nine normal men (mean age 27.6 yr) were exposed to continuous lower-body suction pressure (LBSP) of -20 to -50 mmHg (for 5 min at each level) on four different occasions after having consumed a single oral therapeutic dose of either diltiazem, nifedipine, verapamil, or a placebo, randomly, in a single blind manner. The suction was applied at 12.30 pm in all experiments, while the medications were administered in such a manner so that their expected peak plasma levels would have been achieved at the time of suction application. The cardiovascular reflex effects commenced at a pressure of -30 mmHg, and peaked at -50 mmHg. The increases in the heart rate for all treatments at -50 mmHg was statistically similar (about 16-20 beats/min). The systolic BP fell by about 9 mmHg for the placebo experiments, and this change was not different from the changes produced by the 3 Calcium channel blocker treatments. The diastolic BP increase was about 3 mmHg. The Cardiac index did not vary significantly. Our results suggest that the commonly used Ca++ channel blockers do not adversely affect orthostatic tolerance.

Prevention of oculocardiac reflex (O.C.R) during extraocular muscle surgery.

In the present study the effectiveness of intravenous atropine sulphate which blocks the peripheral muscarinic receptors at the heart and retrobulbar xylocaine hydrochloride which blocks the conduction at ciliary ganglion on the afferent limb of OCR was studied during strabismus surgery. The study was conducted on fifty three patients of either sex having squint of more than ten years duration. The patients were randomly allocated into four groups. No preanaesthetic medication with atropine or retrobulbar block with xylocaine was given in control group of patients. In the second group, only preanaesthetic medication with atropine was given; while in the third group only retrobulbar injection of xylocaine was given five minutes before operation. In the last group both atropine as preanaesthetic medication and xylocaine as retrobulbar block were given. The electrocardiographic recordings were taken before and throughout the operative procedure. It was interesting to note that in the group where atropine and xylocaine were used none of the patients exhibited activation of OCR. Results have been discussed.

Effect of intracerebroventricular administration of angiotensin II on emetic reflex in dogs.

Area postrema is rich in angiotensin II receptors and intravenous (iv) administration of angiotensin II has been reported to elicit emesis. However, in the present study intracerebroventricular (icv) administration of angiotensin II up to a dose of 10 micrograms failed to elicit emesis. It is suggested that presence of a cerebrospinal fluid-brain barrier in area postrema most probably prevents access of icv angiotensin II to its receptors which are otherwise accessible on iv administration.

Action of some amides of substituted ethylenediamines on central nervous system.

Five of the substituted ethylenediamine amides (LMG I to V) were tested for various CNS attributes and for acute toxicity (24 hr mortality). All compounds were potent analgesics in various animal tests, LMG V being most potent. All reduced spontaneous activity of mice and potentiated ether anaesthesia. However, CAR was not altered and anti-MES were not pronounced in rats. Compounds appear to have a wide safety margin considering ED50 and LD50 in mice.