
%0 Journal Article
%A Smythe, GA 
%A W Duncan, M 
%A Bradshaw, JE 
%A Nicholson, MV 
%T Effects of 6-Methoxy-l,2,3,4-tetrahydro-b-carboline and Yohimbine on Hypothalamic Monoamine Status and Pituitary Hormone Release in the Rat
%J Australian Journal of Biological Sciences
%D 1983/10/01
%V 36
%N 4
%P 379-386
%K 
%R https://doi.org/10.1071/BI9830379
%U https://www.publish.csiro.au/paper/BI9830379 
%X Shortly after administration of 6-methoxy-1,2,3,4-tetrahydro-ft-carboline (6-MeOTHBC) and yohimbine to normal or hypothyroid rats [the latter exhibiting chronically elevated levels of serotonin (5-HT) neuronal activity in the hypothalamus] there was a highly significant increase in hypothalamic noradrenaline (NA) activity and in ACTH release concomittant with a reduction in hypothalamic 5-HT activity (P< 0'01) and in growth hormone (GH) (P<O'01) and in thyroid stimulating hormone (TSH) (P< 0'01) release from the pituitary. Both compounds caused an increase in hypothalamic dopamine (DA) metabolism and in pituitary prolactin (PRL) release in normal rats (P<0'01) but only yohimbine exerted this action in hypothyroid rats. Lower doses of 6-MeOTHBC exerted a relatively specific effect in hypothyroid rats, reducing (P< 0·01) 5-HT neuronal activity in parallel with pituitary TSH secretion (P<0·05). While gross effects of 6-MeOTHBC and yohimbine were similar with respect to their effects on NA and 5-HT status in the hypothalamus, there were quantitative differences. 6-MeOTHBC always caused a greater decrease in 5-HT turnover and a lesser increase in NA turnover than did yohimbine. 
