GABA release from interneurons in VTA, projections from the nucleus accumbens (NAc), and rostromedial tegmental nucleus (RMTg) was selectively activated in rat brain slices. The inhibition induced by μ-opioid agonists was pathway dependent. Morphine induced a 46% inhibition of IPSCs evoked from the RMTg, 18% from NAc, and IPSCs evoked from VTA interneurons were almost insensitive (11% inhibitio...

As one of the most important diffused brain modulatory systems, the nucleus locus coeruleus (LC) receives most of its afferents from the nucleus paragigantocellularis (PGi) and plays a major role in the control of drug dependence and some emotional and exciting states. For detailed investigation of the effect of morphine on relationship between these two brain stem nuclei, the activity of the r...

Introduction: Motor behavior and coordination impairment are known side effects of opioid treatment, yet very few studies have investigated the effects of tramadol on motor behavior, or compared its effect with the effect of an opioid. This study investigates the effects of chronic injection of morphine and tramadol on rat motor function during infancy. Methods: Neonate rats (n=56) were randoml...

We evaluated the modulation by Na+,K+-ATPase inhibitors of morphine-induced antinociception in the tail-flick test and [3H]naloxone binding to forebrain membranes. The antinociception induced by morphine (1-32 mg/kg, s.c.) in mice was dose-dependently antagonized by ouabain (1-10 ng/mouse, i.c.v.), which produced a significant shift to the right of the morphine dose-response curve. The i.c.v. a...

introduction: methadone has been used as a drug to detoxify opioid tolerance. naloxane precipitated morphine withdrawal behaviours were attenuated by venlafaxine as an antidepressant. on the contrary, after detoxifying the opioids, spontaneous withdrawal syndrome may occur with pain sensitivity. therefore the present study aimed to examine the effects of chronic methadone (70 mg/kg, in drinking...

conclusions chronic use of opioids may lead to alterations in sexual features and sexual hormones. therefore, opioids have the potential to cause infertility. these changes may result from the effect of the drugs on the hypophysis or hypothalamus, the direct effect of the drugs on the seminiferous tubules, or a combination of both. the findings suggest that public awareness about addiction may ...

introduction: consumption of morphine, during pregnancy, in addition to inducing defects in the mother’s nervous system function, caused defects or delays in the formation and evolution of embryonic visual system. in the present study, changes in lens development were assessed in embryos exposed to morphine in utero. methods: female wistar rats (250-300 g) were mated with male rats and pregnanc...

the purpose of the present study was to evaluate anti-nociceptive effects of morphine, tramadol, meloxicam and their combinations in rats. seventy male wistar rats were divided into seven equal groups and randomly assigned to receive intraperitoneal saline (s) (control group, 1.0 ml kg-1), morphine (mo) (4.0 mg kg-1), tramadol (tr) (12.5 mg kg-1), meloxicam (ml) (1.0 mg kg-1), tramadol- morphin...

objective some lines of evidences demonstrate that opioids are involved in water and food intake. on the other hand the dopaminergic mesolimbic system that consists of ventral tegmental area (vta), nucleus accumbens (nac) and medial prefrontal cortex is considered to be crucial in the rewarding actions of opiates. there are also reports showing that this system has some roles in appetite and dr...