Interaction between the lateral hypothalamic area (LHA) and the medial septal area (MSA) in the control of sodium and potassium excretion in rats

Abstract In studies of the role of the hypothalamus in regulating body ionic balances it was found that carbachol injected into the lateral hypothalamic area (LHA) and medial septal area (MSA) elicited an increase in natriuresis and kaliuresis. This efflux reached its peak between 40 and 60 minutes after such injections. A blockage of this response was observed when LHA stimulation by carbachol was performed in animals whose MSA had been blocked previously by atropine or destroyed by electrolytic lesion. Similarly, stimulation of the MSA after pharmacological blockade or destruction of the LHA elicited a response of greatly decreased intensity. On the basis of these results it was concluded that the natriuretic-kaliuretic response elicited by cholinergic stimulation of the LHA depends in part on synapses located in MSA; the response elicited by cholinergic stimulation of the MSA utilized also synapses located in the LHA, unilaterally and bilaterally.