Morphometric plasticity of nitric oxide containing neurons in the barrel cortex of de-whiskered rats

The rodent somatosensory barrel cortex is an ideal model to examine the effect of experience-dependent plasticity on developing brain circuitry. Sensory deprivation such as whisker deprivation may affect neuroanatomical aspects of the brain during developmental processes. The present study designed to investigate the possible effects of whisker deprivation on the morphometric characteristics of NADPH-d positive neurons in the barrel field cortex of adolescent rats. Pups were divided into the intact [n=4] and whisker-deprived groups [n=4]. In whisker-deprived group, the total whiskers of subjects were trimmed every other day from postnatal day [PND] 0 to PND 60. NADPH-d histochemistry reaction was processed to quantitatively analyze the feature of NADPH-d containing neurons of barrel cortex. Our results showed that the number of NADPH-d positive neurons remained unchanged in whisker-deprived group compared to controls. The mean soma diameter, dendritic length and the number of 3[rd] order processes were significantly decreased in the whisker-deprived rats [p<0.05]. Our results indicate that postnatal whisker deprivation possibly alter NADPH-d/NOS neuronal features in the barrel cortex. The functional implications of these data may relate the plasticity of synaptic receptive field and developmental brain circuits

intracerebroventricular [ICV] administration of w-7, a calmodulin inhibitor, attenuates the development of morphine tolerance in rats

The present study was performed to determine the effect of intracerebroventricular [ICV] administration of W- 7, a specific calmodulin inhibitor, on the development of tolerance to antinociceptive effect morphine administration. This study was carried out on male wistar rats, weighing 200-250 g. Morphine was administered daily [15 mg/kg for 8 days]. The threshold to thermal nociceptive stimuli was measured by tail-flick test. W-7 [0.25, 0.5 and 1 micro mol/rat] was injected through ICV. Maximal possible effect percentage [MPE%] was considered as analgesia index. Our result showed that chronic morphine exposure induced tolerance to its antinociceptive effect and administration of W-7 [0.5 and 1 micro mol/rat] decreased the development of tolerance to it. In conclusion these data showed that chronic injection of W-7 inhibited the development of morphine tolerance which indicates that calmodulin and its dependent pathways may play a role in the morphine tolerance processes