The influence of sex in determining responses to opioid analgesics has been well established in rodents and monkeys in assays of short-lasting, phasic pain. The purpose of this investigation was to use a capsaicin model of tonic pain to evaluate sex differences in hyperalgesia and mu-opioid-induced antihyperalgesia in Fischer 344 (F344) rats. Capsaicin injected into the tail produced a dose-dep...

The aim of the present study was to investigate the effect of α2-adrenergic agonist (xylazine) andantagonist (yohimbine) on phasic pain during estrous cycle in female rats. Adult female rats weighing 180-220 g were kept under controlled temperature (21-24°C) and light/dark conditions (light on at 6:00 a.m. and light off at 6:00 p.m.). Animals were divided into four groups: 1) control group whic...

OBJECTIVE To assess whether "phasic" exercises, including rapid eye-head-neck-arm movements, can benefit patients with chronic cervical injuries. DESIGN A randomized, controlled, double blind study involving 30 chronic patients, who were allocated to either group 1 or group 2. The study period was for 8 wk. SETTING The study was conducted in a private practice. PATIENTS Thirty chronic mot...

The pathophysiological mechanisms of myofascial temporomandibular disorders (TMD) are still under investigation. The hypothesis that TMD pain is caused by a generalized sensitization of higher order neurons in the nociceptive pathways combined with a decreased efficacy of endogenous inhibitory systems has recently gained support in the literature. This study was designed to further investigate ...

Studies have shown that N-methyl-D-aspartate (NMDA) receptors play a critical role in pain processing at different levels of the central nervous system. In this study, we used female adult Wistar rats to examine the effects of antagonizing the NR2B subunit of the NMDA receptor in phasic and tonic pain processes. All the rats underwent stereotaxic surgery for cortical cannula implantation and af...

BACKGROUND Studies have shown that N-methyl-D-aspartate (NMDA) receptors play a critical role in pain processing at different levels of the central nervous system. METHODS In this study, we used adult Wistar rats to examine gender differences in the effects of NR2B NMDA antagonism at the level of the anterior cingulate cortex in phasic pain, and in the first and second phases of a formalin te...

A close relationship exists between calcium concentration in the central nervous system and nociceptive processing. Aminoglycoside antibiotics and magnesium interact with N- and P/Q-type voltage-operated calcium channels. In the present study we compare the antinociceptive potency of intrathecal administration of aminoglycoside antibiotics and magnesium chloride in the tail-flick test and on in...

amitriptyline, a tricyclic antidepressant agent is used as one of the analgesic drugs in different kinds of pain. in the present study the effect of local (subcutaneous) injection of amitriptyline (50 and 100 µg) on the acute and chronic pain using formalin test, was investigated. our data show that local injection of amitriptyline to the paw receiving formalin, causes a decrease in pain in bot...

Various physiological parameters including level of sex steroids undergo alterations following chronic administration of morphine. In this study, the effect of chronic administration of morphine on phasic and tonic pain was studied in morphine-dependent male and female rats in the presence and absence of gonads using formalin test. In addition, for evaluation of differences in dependency, withd...