Various physiological parameters including level of sex steroids undergo alterations following chronic administration of morphine. In this study, the effect of chronic administration of morphine on phasic and tonic pain was studied in morphine-dependent male and female rats in the presence and absence of gonads using formalin test. In addition, for evaluation of differences in dependency, withd...

introduction: although tolerance to and dependence on opioids are characterized by excessive activity of camp pathway in some brain stem nuclei, the impact of morphine dependence on activity of camp pathway in paragigantocellularis nucleus (pgi), located in the rostral ventrolateral medulla, remains unclear. therefore, the effect of adenyl cyclase activator forskolin on spontaneous firing rate ...

In this study the effect of adenosine and caffeine on spontaneous activity of paragigantocellularis (PGi) neurons was investigated. The spontaneous activity of PGi neurons was significantly decreased by microinjection of adenosine (10 nM, 0.5 µl) into PGi nucleus of both control and morphine-dependent rats. The decrease in firing rate of PGi neurons of morphine-dependent rats was greater than t...

Introduction:Adenosine as a potent vasodilator has physiological role in regulation of regional cerebral blood flow (rCBF). Metod: Laser-Dِoppler flowmetry technique was used to study pial vessels blood flow responses to adenosine receptors agonists and antagonist. Male Sprague Dawley rats (250-350g) that were housed in standard conditions, were anesthetized with Urethane (1.5g/kg). Adenosine ...

there are several conflicting evidences showing the effect of morphine on learning and memory processes. in the present study the effect of chronic morphine administration on passive avoidance, active avoidance and spatial learning and memory of morphine dependent male rats using passive avoidance shuttle box and morris water maze tasks were investigated, respectively. male rats received morphi...

introduction: the aim of this study was to evaluate the changes in camp and some other cellular ingredients following adenyl cyclase activation in paragigantocellularis (pgi) neurons of morphine dependent and withdrawn rats. material and methods: the 3.5 mm thick brainstem slice prepared from pgi area (-10.04 to -13.24 from bregma) of control and morphine dependent rats (n=5 in each group). wer...

previous studies have shown that the receptive field properties, spontaneous activity and spatio-temporal interactions of low-threshold mechanical somatosensory cells in the barrel cortex are influenced by c-fibers. in this study, we examined the effect of c-fiber depletion on response properties of barrel cortex neurons following experience dependent plasticity. methods: in this study, exterac...

Acute morphine withdrawal is considered to be the physical manifestation of dependence, emerging when morphine administration is stopped or after the administration of an opiate antagonist, such as naloxone. Gabapentin, which is an antiepileptic, agent, enhances the analgesic effect of morphine in healthy volunteers, but its effect on morphine dependence and withdrawal signs has not determined ...

Acute morphine withdrawal is considered to be the physical manifestation of dependence, emerging when morphine administration is stopped or after the administration of an opiate antagonist, such as naloxone. Gabapentin, which is an antiepileptic, agent, enhances the analgesic effect of morphine in healthy volunteers, but its effect on morphine dependence and withdrawal signs has not determined ...