Recent studies have implicated the involvement of Ca2+-dependent mechanisms, in particular, calcium/calmodulin-protein kinase II in nicotine-induced antinociception using the tail-flick test. The spinal cord was suggested as a possible site of this involvement. The present study was undertaken to investigate the hypothesis that the beta2 nicotinic receptor subunit plays a central role in nicoti...

It is well established that the vanilloid receptor, VR1, is an important peripheral mediator of nociception. VR1 receptors are also located in several brain regions, yet it is uncertain whether these supraspinal VR1 receptors have any influence on the nociceptive system. To investigate a possible nociceptive role for supraspinal VR1 receptors, capsaicin (10 nmol in 0.4 microl) was microinjected...

BACKGROUND 5-HT(1A)-R-agonist repinotan was shown to counteract a morphine-induced ventilatory depression but had pronociceptive effects at small doses (0.2 μg/kg). It remained to be clarified (1) whether a moderate dose of repinotan, sufficient to stimulate spontaneous breathing, impairs antinociception if plasma concentration decreases over time, and if (2) moderate doses prevent ventilatory ...

Nerve growth factor (NGF) induces a relatively long-term hyperalgesia in rats, whereas substance P (SP) N-terminal fragments, like SP(1-7), produce a long-lasting antinociception in mice. We used various nociceptive assays to compare the effects of these compounds on pain transmission when injected intrathecally (i.t.) in mice, and to determine whether either compound affects the action of the ...

The zona incerta (ZI) is a subthalamic nucleus connected to several structures, some of them known to be involved with antinociception. The ZI itself may be involved with both antinociception and nociception. The antinociceptive effects of stimulating the ZI with glutamate using the rat tail-flick test and a rat model of incision pain were examined. The effects of intraperitoneal antagonists of...

Previous studies showed the role of basolateral amygdala (BLA) in cannabinoid-induced antinociception. Furthermore, the nucleus accumbens (NAc) plays an important role in mediating the suppression of pain in animal models. The present study extended the role of dopamine receptors within the NAc in antinociceptive effect of cannabinoid receptor agonist, WIN55,212-2, microinjected into the BLA fo...

Pain is the most pronounced complaint of women with endometriosis, however the underlying mechanism is still poorly understood. In the present study, the authors evaluate the effect of transient receptor potential vanilloid type 1 (TRPV1) of dorsal root ganglia (DRG) on endometriosis-associated pain. A total of 36 SD rats were randomly divided into a sham group (n=9) and a Model group (n=27), a...

BACKGROUND Apelin has various effects on a lot of systems such as central nervous system and cardiovascular system. This study investigated the possible analgesic effects of apelin-13 using the hot-plate and the tail-flick thermal analgesia tests in rats. We also evaluated the mechanism underlying the analgesic effects of apelin-13 by pretreating with Nw-nitro-L-arginine methyl ester (L-NAME) o...

Three hundred feedlot steers (320 +/- 2 kg) were assigned to freeze brand, hot-iron brand, and sham branding treatments according to a randomized branding arrangement. Behaviors believed to be indicative of pain (i.e., tail-flicking, kicking, falling, and vocalizing) were recorded during branding. Escape behavior, measured as the amount and duration of force exerted on the headgate and squeeze ...