Cue-induced drug-seeking in rodents progressively increases after withdrawal from operant self-administration of cocaine, heroin, methamphetamine, and alcohol, a phenomenon termed "incubation of drug craving." Here, we used the opiate drug morphine and explored whether incubation of drug craving also occurs in a pavlovian conditioned place preference (CPP) procedure in which rats learn to assoc...

In opioid-dependent subjects, the low-efficacy mu agonist nalbuphine generally precipitates withdrawal or withdrawal-like stimulus effects. To provide a more complete characterization of the discriminative stimulus effects of nalbuphine in opioid-treated subjects, seven White Carneux pigeons were treated daily with 10 mg/kg morphine i.m. and trained 6 h later to discriminate among 10 mg/kg morp...

in this study, we investigated the interactive effects of intraperitoneal (i.p.) injections of three different phosphodiesterase inhibitors (pdeis) on morphine-induced analgesia in mice using tail-flick method. subcutaneous administration of morphine (1, 3 and 6 mg/kg) caused significant antinociceptive effects in a dose dependent manner. administration of pentoxifylline (12.5, 25, 50 and 100 m...

introduction: the role of midbrain reticular formation, which includes the nucleus cuneiformis (ncf), as a crucial antinociceptive region in descending pain modulation has long been investigated. in this study, we tried to highlight the role of ncf in morphine-induced antinociception in formalin-induced pain model in rats. methods: a total of 201 male wistar rats weighing 260-310 g were used in...

Evidence indicates that medial septum nicotinic receptors regulate cognitive process. Ghrelin is a gut hormone that regulates energy homeostasis. Ghrelin also is produced in brain and known to be involved in cognitive function. The purpose of the study was to evaluate the effects of medial septal injection of ghrelin on morphine-induced memory impairment in rats. Also, the possible relationship...

It has been reported that morphine tolerance does not develop in the presence of chronic pain. Therefore, this study was conducted to find out whether chronic inflammatory pain is able to eliminate or attenuate the developed tolerance to analgesic effect of morphine and also to investigate the role of lumbar spinal cord as a candidate site for this interaction. Tolerance was induced in adult ma...