RESUMO
Calcitonin is a peptide hormone which can act centrally to decrease food intake and locomotor activity, and increase body temperature and nociceptive thresholds. In a previous study we showed that the brain sites involved in the food intake and locomotion decreases were mostly the paraventricular nucleus, the perifornical area and the preoptic area above the optic chiasma. We now study the diencephalic sites involved in calcitonin-induced increases in body temperature and nociceptive thresholds. Salmon calcitonin (15 ng in 0.3 microliters) was injected in several diencephalic sites, and the effects on body temperature and nociceptive thresholds compared with a saline injection. The results show that the sensitive sites are the dorsomedial nucleus of the hypothalamus, the preoptic area and the centromedial nucleus of the thalamus, and not the paraventricular nucleus and adjacent perifornical area. Therefore, different kinds of central effects of calcitonin can be differentiated on an anatomical basis.
Assuntos
Analgesia , Analgésicos/farmacologia , Calcitonina/farmacologia , Diencéfalo/fisiologia , Febre/fisiopatologia , Atividade Motora/efeitos dos fármacos , Dor/fisiopatologia , Animais , Temperatura Corporal/efeitos dos fármacos , Diencéfalo/fisiopatologia , Dipeptídeos/farmacologia , Feminino , Febre/induzido quimicamente , Masculino , Ratos , Ratos Sprague-Dawley , Fatores Sexuais , Fatores de TempoRESUMO
The calcium channel inhibitor diltiazem is widely used as a medication for cardiovascular diseases. Some side effects have been reported after its administration, including changes in activity (apathy or hyperactivity) and feeding behavior (anorexia). Previous experiments have found that local administration of various peptides into the paraventricular nucleus of the hypothalamus can have profound effects on these two behaviors. In the present study, effects of local infusions of diltiazem into the paraventricular nucleus on locomotor activity and food intake have been tested. A marked hyperactivity, greater than the hyperactivity caused by intraperitoneal injection of amphetamine was produced. Feeding behavior was not affected one hour after the infusions but intraventricular diltiazem infusions decreased feeding behavior. It is concluded that the paraventricular nucleus of the hypothalamus has an important role in the regulation of locomotor activity and that diltiazem can act at this level to produce behavioral changes.
Assuntos
Diltiazem/administração & dosagem , Comportamento Alimentar/efeitos dos fármacos , Atividade Motora/efeitos dos fármacos , Núcleo Hipotalâmico Paraventricular/efeitos dos fármacos , Anfetamina/administração & dosagem , Anfetamina/farmacologia , Animais , Diltiazem/farmacologia , Região Hipotalâmica Lateral/efeitos dos fármacos , Injeções Intraperitoneais , Injeções Intraventriculares , Masculino , Ratos , Ratos EndogâmicosRESUMO
Calcitonin receptors are found in the brain, and intracerebral infusions of calcitonin can produce behavioral effects. Among these behavioral effects are decreases in food intake and decreases in amphetamine-induced locomotor activity. In previous experiments we found that decreases in food intake were induced by local administration of calcitonin into several hypothalamic sites and into the nucleus accumbens. In the present experiment calcitonin decreased locomotor activity when locally injected into the same sites where it decreases food intake. The areas where calcitonin is most effective in decreasing locomotor activity are located in the hypothalamus and nucleus accumbens, suggesting that these areas are the major sites of action of calcitonin in inhibiting amphetamine-induced locomotor activity.