Misra et al. (1971) found that 1 h after a single subcutaneous injection of [N-Me-l4C1morphine into the rat, three radioactive compounds could be extracted from the cerebral cortex, namely free morphine, morphine 3-glucuronide and a ‘non-acid-hydrolysable’ conjugate. The regional and subcellular distribution of morphine and its metabolites in brain after subcutaneous injection has never been st...

  The effects of chronic morphine administration on the development of long-term potentiation (LTP) were investigated at the Schaffer collateral-CA1 pyramidal cell synapses of the rat hippocampal slices using primed-bursts tetanic stimulation. Significant enhancement of orthodromic population spike (OPS) was found for all stimulus intensities after tetanic stimulation. OPS enhancement was great...

background: role of nitric oxide (no) in morphine-induced conditioned place preference (cpp) has already been proposed in the rat medial septum (ms), but no molecular evidence has been provided to clear this fact. methods: effects of intraseptal injections of l-arginine and/or ng-nitro-l-arginine methyl ester (l-name) on morphine place conditioning in wistar rats were examined. morphine (2.5-7....

Introduction: There is some evidence supporting the reduced activity of integrins following chronic administration of morphine. This reduction might play a role in morphine tolerance development. Manganese binds to the extracellular domain of integrins and makes them to be activated. The effect of integrins activation using manganese on tolerance development to the analgesic effect of morphine ...

Morphine's effects on learning and memory processes are well known to depend on synaptic plasticity in the hippocampus. Whereas the role of the hippocampus in morphine-induced amnesia and state-dependent learning is established, the biochemical and molecular mechanisms underlying these processes are poorly understood. The present study intended to investigate whether administration of morphine ...

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 rand...

In the present study, effects of intra-hippocampal CA1 (intra-CA1) injections of GABA(B) receptor agonist and antagonist on the acquisition and expression of morphine-induced place preference in male Wistar rats have been investigated. Subcutaneous administration of different doses of morphine sulphate (0.5-6 mg/kg) produced a dose-dependent conditioned place preference (CPP). Using a 3-day sch...

background and objective: the effect of opioids on the reproductive system has been studied as an attractive research field. in this study, the effect of morphine as an analgesic opioid was evaluated on the ovarian polycystic induction in the rat. materials & methods: in this study, 24 female virgin wistar rats weighing 200-250 g were injected with morphine (1-10 mg/kg/day) for 9 days. cont...

Endogenous opioid system agonists exert amnestic effects in different models of memory. It has been suggested that these amnestic effects may be linked indirectly to state-dependent learning. Accordingly pre-training administration of morphine can impair the retrieval of learned tasks in a state dependent manner, which is reversible by pre test morphine administration. In this study, state depe...