Effect of glutamate and angiotensin II on whole cell currents and release of nitric oxide in the rat subfornical organ.
Blood-borne angiotensin II (AngII) is known to mediate water-intake by its excitatory effect on neurons in the subfornical organ (SFO). Conversely, nitric oxide (NO) has exclusively inhibitory effects on rat SFO-neurons and on SFO-mediated water-intake. Extracellular and patch-clamp recordings from freshly dissociated rat SFO-neurons showed that glutamate activates AngII-sensitive SFO-neurons by opening ligand-gated cation channels. An immunocytochemical study showed that activation of glutamate receptors increased the concentration of the inhibitory second messenger cGMP in the SFO. A model is proposed suggesting that NO protects SFO-neurons from overexcitability by excitatory neurotransmitters.
Schmid
H A
HA
Max-Planck-Institute for Physiological and Clinical Research, Bad Nauheim, Federal Republic of Germany.
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D006152:Cyclic GMP / Q000096:biosynthesis; D018698:Glutamic Acid / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D051381:Rats; D013356:Subfornical Organ / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism
D000804:Angiotensin II; D009569:Nitric Oxide; D018698:Glutamic Acid; D006152:Cyclic GMP