Sympatho-inhibitory mechanisms acting at sympathetic ganglia to attenuate hypothalamic-induced pressor effect in the cat.

Pressor and tachycardic effects induced in the cat by stimulation of a lateral hypothalamic (LH) site, are shown to be mediated by sympathetic ganglia nicotinic receptor, and potentiated under atropine methyl nitrate sympathetic ganglia blockage. It is postulated that a sympatho-inhibitory pathway muscarinic ganglionic mechanism, co-activated by the LH stimulation, attenuates the pressor and tachycardic effects, the potentiation presumably being a manifestation of blockage of that mechanism.