Heterogeneous actions of vasopressin on ANG II-sensitive neurons in the subfornical organ of rats

The American Journal of Physiology
N AnthesE Simon

Abstract

The aim of this study was to investigate the effects of the antidiuretic hormone arginine vasopressin (AVP), which is released in vivo during dehydration and hypovolemia to prevent further water loss, on the activity of neurons in the subfornical organ (SFO). The SFO is a brain structure with an open blood-brain barrier and is critically involved in angiotensin II (ANG II)-dependent water intake. SFO neurons were recorded extracellularly in tissue slices of the rat brain and were tested for responsiveness to AVP and ANG II. About one-half of 159 neurons tested with an AVP concentration of 10(-6) M in the superfusion medium were responsive, and approximately equal proportions were excited and inhibited. Neurons exhibiting the different response types did not differ from each other with respect to spontaneous discharge rate, latency, and duration of the response. Excitatory and inhibitory responses to AVP were dose dependent and reversible, and their threshold concentrations (10(-8) to 10(-9) M) were similar. Superfusion with a medium low in Ca2+ and high in Mg2+ showed that the excitatory effect is most likely direct, whereas the inhibitory effect largely depends on inhibitory synaptic interaction. About one-half of the SFO neur...Continue Reading

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Citations

Aug 31, 2012·American Journal of Physiology. Regulatory, Integrative and Comparative Physiology·Jason M MoreauJohn Ciriello
Jan 17, 2014·American Journal of Physiology. Regulatory, Integrative and Comparative Physiology·Al-Shaimaa F AhmedKeith A Sharkey
May 14, 2010·American Journal of Physiology. Regulatory, Integrative and Comparative Physiology·Pauline M Smith, Alastair V Ferguson
Dec 23, 2016·American Journal of Physiology. Regulatory, Integrative and Comparative Physiology·Nicole M Cancelliere, Alastair V Ferguson

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