It is now well established that the analgesic actions of opioids can be modified by "anti-analgesic" or "antiopioid" peptides, among them cholecystokinin (CCK). Although the focus of much recent work concerned with CCK-opioid interactions has been at the level of the spinal cord, CCK also acts within the brain to modify opioid analgesia. The aim of the present study was to characterize the acti...

In this study, we characterized the role of delta-1 and delta-2 opioid receptors in the ventromedial medulla (VMM) in the modulation of thermal nociception. Male Sprague-Dawley rats were prepared with an intracerebral guide cannula aimed at the nucleus raphe magnus or nucleus reticularis gigantocellularis pars alpha. Microinjection of the delta-1 opioid receptor agonist [D-Pen2,D-Pen5]enkephali...

In this study, we examined whether Sprague-Dawley rats obtained from two different vendors, Harlan and Sasco, differ with respect to the types of alpha-2 adrenoceptors in the spinal cord that mediate antinociception. This hypothesis was tested using two alpha-2 adrenoceptor agonists, dexmedetomidine and ST-91, which are relatively selective for alpha-2A and alpha-2B adrenoceptors, respectively,...

Zinc is concentrated in the dorsal horn of the spinal cord and has been proposed to alter excitability of primary afferent C-fibers, structures believed to be important in nociceptive transmission. Based on the inhibitory effect of zinc on the activity of various other neurotransmitters that play a role in nociception, we tested the hypothesis that zinc modulates pain transmission. To test this...

Resveratrol has been widely investigated for its potential health properties, although little is known about its mechanism in vivo. Previous studies have indicated that resveratrol produces antinociceptive effects in mice. Calcium channels and calcium/caffeine-sensitive pools are reported to be associated with analgesic effect. The present study was to explore the involvement of Ca2+ channel an...

This study investigated the role of K(ATP) channels in morphine-induced antinociception and hepatic oxidative stress in acute and inflammatory pain. The K(ATP) channel modulators (K(ATP) channel opener, diazoxide 100 mg/kg, p.o, and K(ATP) channel blocker, glibenclamide, 3 mg/kg i.p.) were administered with morphine (80 mg/kg, i.p.). Antinociception was assessed by the tail-flick and formalin t...

BACKGROUND Intrathecal administration of 5-hydroxytryptamine (5-HT) is antinociceptive to noxious heat and electrical stimuli. The contributions of different receptor subtypes to the antinociceptive effects of 5-HT are controversial. The main reasons for this are the poor receptor subtype selectivity of some agonist drugs and the difficulty of restricting drug action to the spinal cord in some ...

In this study we used the chronic (formalin test) and acute (tail flick) pain models of rats for evaluation of probable analgesic and anti-inflammatory effect of Sambucus ebulus (Se) rhizome extract. Sodium salicylate (SS) was used as a positive control. A total of 300 mg/kg of SS (i.p.) had no effect on tail flick latency, while 100 and 200 mg/kg i.p. of extract increased this latency (P < 0.0...

Corydalis yanhusuo. W.T. extracts (YHS) are widely used for the treatment of pain and inflammation. There are a few studies that assessed the effects of YHS in pain assays; however, none of these studies has systematically compared its activities in the different pain animal modes namely: acute, inflammatory and chronic pain. Furthermore, little is known about the mechanism of YHS activity in t...