this research was designed to study sexual differences in place conditioning induced by morphine in offspring born of female wistar rats mated with drug-naïve males. mothers were exposed to morphine during the 14th-16th days of gestational. control dams were simply saline-injected. female and male virgin offspring born of morphine-treated or saline-treated mothers were separately housed until b...

abrupt cessation of morphine leads to withdrawal signs and cognitive deficits. endocannabinoid system is activated during withdrawal; therefore, the aim of the present study was to assess the effects of am281, cannabinoid antagonist/inverse agonist, on memory deficit following spontaneous morphine withdrawal. cognition was evaluated by using the object recognition task. the novel object recogni...

Morphine administered simultaneously to intracerebroventricular (i.c.v.) and intrathecal (i.t.) sites exhibits synergism, with the antinociceptive potency much greater than would be predicted from a simple addition of the potencies of the same dose administered to either site alone. This synergism was quantified in mice using both a fixed dose method, in which the morphine dose at one site was ...

Introduction: Several studies have reported anti-anxiety effects of morphine in adult rats. The present study examined the effect of chronic morphine injections in infancy and before puberty on anxiety-like behavior in immature rats. Methods: Neonate rats (n=35) were randomly chosen and divided into two groups. On postnatal days 8-14, one group received saline and the other one received mor...

The present study evaluates the influence of cholera toxin and its B-subunit on thermic responses to morphine in the rats. The holotoxin (1 microg/rat) and the B-subunit (5 microg) were administered ICV and three days later rats were challenged ICV with morphine and tested for changes of body temperature. Cholera toxin, but not its B-subunit, modified the time course of the hyperthermic respons...

The duration of respiratory depression induced by morphine 10 mg/70 kg was studied following the administration of one of two opioid antagonists. Respiratory measurements included: (i) the ventilatory response to carbon dioxide, described in two ways--the minute ventilation at an end-tidal carbon dioxide partial pressure of 8 kPa (VE8) and the log slope of the ventilatory response to carbon dio...

The effects of repeated administration of morphine and methadone, followed by a challenge dose of either morphine or methadone were examined ex vivo in rat frontal cortical slices that were prepared 1 h after final drug administration. Morphine challenge dose (5 mg/kg), administered 14 days after the end of repeated morphine pretreatment (10 mg/kg, administered 7 times) decreased both the AMPA/...