The effects of highly selective mu and delta opioid peptide agonists were determined in two rat models of experimentally-induced convulsions, the flurothyl threshold test and the maximal electroshock test. Intracerebroventricular injections of the mu selective enkephalin DAGO (0.3-2.2 nmol) resulted in a dose-related protection in both seizure models. Pretreatment with a low dose of naloxone (2...

objectives: crocin, a constituent of saffron and yellow gardenia, possesses anti-nociceptive effects. in the present study, we investigated the effects of intra-fourth ventricle injection of crocin in a rat model of orofacial pain. the contribution of opioid system was assessed using intra-fourth ventricle injection of naloxone, an opioid receptor antagonist. materials and methods: a guide cann...

introduction: it is known that acute and chronic stress induce hormonal and neuronal changes which affecting both pain threshold and nociceptive behaviours. orexin plays an important role in modulation of pain and stress. considering pain modulation during stress and the role of orexin in pain and stress, orexin might be involved in pain modulation during stress.we evaluated the involvement of ...

We have previously demonstrated that both endomorphin-1 and endomorphin-2 produce their antinociception by the stimulation of mu-opioid receptors. However, the antinociception induced by endomorphin-2 contains an additional component, which is mediated by the release of dynorphin A (1-17) acting on kappa-opioid receptors. These studies were done to determine whether the antinociception induced ...

This study examined the effects of intrathecally (i.t.) administered mu and delta opioid receptor agonists on the flinching behavior and the expression of Fos-like immunoreactivity (Fos-LI) in the spinal cord elicited by s.c. injection of 5% formalin in one hindpaw of the rat. Intrathecal pretreatment with either the delta-1 opioid receptor agonist [D-Pen2,5]enkephalin (DPDPE) or the delta-2 op...

primarily opioidergic and adenosine mechanisms are considered to be involved in the antinociceptive effects of antidepressants. this study was designed to determine the efficacy of acute venlafaxine administration in alleviating symptoms of neuropathic pain and the role of endogenous adenosine and opioid systems in this effect of venlafaxine. we have evaluated the effect of caffeine, a non-sele...

To determine the role of spinal mu-opioid receptor subtypes in antinociception induced by intrathecal (i.t.) injection of endomorphin-1 and -2, we assessed the effects of beta-funaltrexamine (a selective mu-opioid receptor antagonist) naloxonazine (a selective antagonist at the mu(1)-opioid receptor) and a novel receptor antagonist (3-methoxynaltrexone) using the paw-withdrawal test. Antinocice...

intraperitoneal (ip) injection of bupropion (3,6, amine (4,16 mg kg•&apos;) induced dose-dependent climbing in mice. the climbing response induced by both drugs were decreased in animals pretreated either with the 0-1 antagonist sch 233<)0 or the 0-2 antagonist sulpiride. the α-adrenoceptor blocker phenoxybenzamine decreased the climbing induced by both bupropion and amphetamine, but the β-adre...

Introduction: It is known that acute and chronic stress induce hormonal and neuronal changes which affecting both pain threshold and nociceptive behaviours. Orexin plays an important role in modulation of pain and stress. Considering pain modulation during stress and the role of orexin in pain and stress, orexin might be involved in pain modulation during stress.We evaluated the involvement ...