Effect of compound 48/80 on mast cells and biogenic amine levels in brain structures and on corticosterone secretion.

The effect of compound 48/80, given intracerebroventricularly, on mast cells (MC) and histamine, serotonin and noradrenaline levels in the hypothalamus, thalamus and hippocampus as well as on corticosterone secretion was investigated in rats. A relatively high amount of mast cells was found in the thalamus, a very low in the hypothalamus and almost none in the hippocampus. Compound 48/80 (1 and 5 micrograms) induced MC degranulation, a significant increase in corticosterone secretion and diminution of the thalamic histamine level. The drug also elicited small biphasic changes in histamine level in the hypothalamus and moderately increased serotonin turnover in the brain structures studied, but did not affect noradrenaline level in those structures. These results indicate that brain MC contain a significant amount of histamine, but not serotonin. Compound 48/80 releases histamine from MC, but does not markedly influence neuronal biogenic amines in the brain structures involved in regulation of the hypothalamic-pituitary-adrenal axis.