Circulatory adaptive reactions under hypergravity in normal and cold environments

Rats subjected to various levels of +Gz acceleration exhibited an increased blood concentration of noradrenalin and adrenalin, indicative of a sympatho-adrenergic reaction. Under the same conditions, from plasma determinations, and by histochemical examination of the supra-optic nucleus, an increased antidiuretic response was noted. This response was reduced in cold environment.