Nefazodone alters NPY immunostaining in rat arcuate-paraventricular projection without changes in food intake and body weight.

Nefazodone is an antidepressant drug that inhibits serotonin and noradrenaline reuptake. The aim of the present work was to study the effects of nefazodone on food intake, body weight, adiposity and hypothalamic NPY immunostaining in rats. For this purpose, male Sprague-Dawley rats (3-month-old) were administered with nefazodone (20 mg/kg; i.p) daily for two weeks. The control group was given 0.9% NaCl solution. Hypothalamic arcuate, paraventricular, periventricular, supraoptic and suprachiasmatic nuclei and the lateral hypothalamic area were immunostained for NPY. Chronic nefazodone administration in rats did not modify food intake, body weight and adipose depot size (subcutaneous, perirenal and epididymal white adipose tissues, and interscapular brown adipose tissue). However, a significant decrease in paraventricular NPY immunostaining was found in the nefazodone group compared with the control group. No changes in other hypothalamic regions such as arcuate, periventricular, supraoptic and suprachiasmatic nuclei, and lateral and medial preoptic areas were observed. Because nefazodone is an alpha1-adrenoceptor antagonist, it can be proposed that the expected decrease in food intake after nefazodone administration, due to its effects on NPY arcuate-paraventricular projection, could be masked by the opposite orexigenic effect of alpha1-adrenoceptor blockade.

Toluene alters mu-opioid receptor expression in the rat brainstem.

Toluene is an ototoxic organic solvent widely used in industry and could be a cause of sleep apnea. Acute toluene administration in rats induces an increase in the number of neural cells immunostained for mu-opioid receptors in several brainstem nuclei, such as the inferior colliculus, dorsal and lateral periaqueductal gray and dorsal raphe, without changes in the superior colliculus and the interpeduncular and lateral reticular nuclei. These data suggest that mu-opioid receptors could be involved in toluene-induced neurotoxic effects on the physiological regulation of breathing during sleep, and auditive function.

Variaciones en la expresión cerebral del receptor opioide mu a lo largo del ciclo estral de la rata / Estrous cycle alters mu-opioid receptor immunostaining in the rat brain

Con el fin de observar las posibles alteraciones regionales de la expresión de receptores opioides mu en el cerebro de la rata que pudieran acontecer a lo largo del ciclo estral, se ha realizado un estudio inmunocitoquímico que ha demostrado la existencia de un incremento significativo del número de células nerviosas que expresan el receptor en la fase de proestro (a las 15.00 h), con respecto al estro, en el área preóptica medial del hipotálamo y la corteza piriforme. Estos resultados concuerdan con estudios previos en los que se ha demostrado que la expresión del receptor opioide mu en el prosencéfalo de la rata puede ser alterada por los esteroides gonadales (AU)