Participation of cholinergic and adrenergic synapses of the medial septal area (MSA) in the natriuretic and kaliuretic responses to intraventricular hypertonic saline (NaCl)

The microinjection of hypertonic sodium chloride into the third ventricle elicits natriuresis and kaliuresis in rats following water loading. These responses were blocked by atropine or phentolamine microinjection into the MSA. The data suggest the interaction between periventricular areas sensible to changes of sodium concentration in the cerebrospinal fluid (CSF) and MSA. Cholinergic and alpha-adrenergic synapses of MSA are involved in this interaction which regulates renal sodium excretion.