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 h ypothalamus, thalamus and hippocampus as well as on corticosterone sec retion was investigated in rats. A relatively high amount of mast cell s was found in the thalamus, a very low in the hypothalamus and almost none in the hippocampus. Compound 48/80 (1 and 5 mu g) induced MC deg ranulation, a significant increase in corticosterone secretion and dim inution 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 ind icate that brain MC contain a significant amount of histamine, but not serotonin. Compound 48/80 releases histamine from MC, but does not ma rkedly influence neuronal biogenic amines in the brain structures invo lved in regulation of the hypothalamic-pituitary-adrenal axis.