Abstract
CACABELOS, R, NIIGAWA, H., NISHIMURA, T., YAMATODANI, A., and WADA, H. Somatostatin-Induced Histamine Response in the Rat Central Nervous System. Tohoku J. exp. Med., 1987, 152 (4), 397-405 - The effects of somatostatin (SS-14) (0.1-10μg, i.c.v.) on brain histamine (HA) in male Wistar rats were investigated. HA was measured by HPLC with a cation exchanger and an automated fluorometric detection system. SS-14 induced time- and dose-dependent changes in the levels of HA in the anterior hypothalamus, posterior hypothalamus, median eminence, adenohypophysis, hippocampus, and frontal cortex. In the anterior hypothalamus, posterior hypothalamus and hippocampus, SS-14 (1μg, i.c.v.) significantly (p<0.01) decreased the levels of HA from 5 to 30min. This response was delayed by 5min in the frontal cortex and adenohypophysis. Only in the neurohypophysis, SS-14 increased the concentration of HA 10min after injection, but this response was not dose-related. These results seem to indicate that SS-14 influences neuronal HA probably modifying HA release, it leading to a decrease of the levels of the biogenic amine in specific areas of the brain. Since this effect is opposite to that developed by growth hormone-releasing factor (GRF) in identical conditions, HA seems to fulfil the criteria by which a neuroendocrine modulator should currently respond in a specific time- and dose-dependent manner to those neuropeptides which modulate. Therefore, HA is likely to play a key role as a neuromodulator of the somatotropinergic system in the rat
