p Chlorophenylalanine (PCPA) administration lowered the hypothalamic serotonin content and facilitated the adrenal response to ether stress. Restoration of adrenal function was, however, delayed and there was no change in basal secretion. Similar changes were obtained after PCPA implantation into the medial hypothalamus. Nialamide treatment increased the hypothalamic serotonin content and blocked the adrenal response to stress. A similar alteration of adrenal function was seen in animals bearing a serotonin implant in the medial hypothalamus. The basal secretion was normal. Reserpine treatment lowered the hypothalamic serotonin content and increased basal adrenal secretion. However, to ether stress there was no response either in hypothalamic serotonin content or in adrenal function. In PCPA pretreated animals after reserpine administration hypothalamic serotonin content was lower and adrenal corticosterone secretion higher than in the animals not subjected to pretreatment. Nialamide pretreatment prevented the decrease in hypothalamic serotonin content induced by reserpine and somewhat blocked the increase in adrenal corticoid secretion. Ether stress was ineffective in altering the hypothalamic serotonin content and adrenal function. PCPA and nialamide pretreatment in combination with reserpine resulted in a low serotonin level in the hypothalamus and a high plasma corticosterone level. The values were similar to those for the PCPA plus reserpine treated group. Ether stress had no effect either on the hypothalamic serotonin level or on the plasma corticosterone level. Pharmacological observations have shown that the changes induced in the stress mechanism by different drugs are related to their action on the hypothalamic serotonin level. Its increase inhibits, while its decrease facilitates, the stress induced activation of pituitary adrenal function. Reserpine induces a constant high corticoid level in the plasma and a low serotonin level in the hypothalamus during the time investigated. This is modified by drugs altering the hypothalamic serotonin level in the same way as the stress induced response in normal animals. However, in these animals there is no additional stress response.
|Number of pages||10|
|Journal||Acta physiologica Academiae Scientiarum Hungaricae|
|Publication status||Published - Dec 1 1973|
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