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Author Yamashita, Hiroshi ♦ Inenaga, Kiyotoshi ♦ Okuya, Shigeru ♦ Hattori, Yukio ♦ Yamamoto, Shigeki
Source J-STAGE
Content type Text
Publisher International Society of Histology and Cytology
Language English
Abstract The effects of angiotensin II (A II) and ANP on spontaneously active neurons in the subfornical organ (SFO), anteroventral third ventricle (AV3V) and supraoptic (SON) and paraventricular nucleus (PVN) were investigated using slice preparations and extracellular recordings. Application of A II $(10^{-7}M)$ excited the neural activity of 66% of the SFO neurons, 28% of the AV3V neurons and 44% of the SON neurons. The threshold concentration to produce responses in SFO and AV3V neuron was less than $10^{-10}M,$ while that in SON neurons was $10^{-9}M.$ The excitatory effects of A II were reversibly antagonized by saralasin and persisted after synaptic blockade in a low $Ca^{2+}$ and high $Mg^{2+}$ medium. Application of ANP $(10^{-7}M)$ inhibited the neural activity of 41% of the AV3V neurons, 22% of the PVN neurons and only 14% of the SFO neurons but had no effect on SON neurons. The threshold concentration for ANP in the AV3V was $10^{-11}M.$ Interestingly, ANP inhibited A II induced excitation in most of the SFO neurons (87%), while ANP had little effects on their spontaneous firing rates. These results show that both peptides of A II and ANP have direct central actions on hypothalamic neurons although ANP can not directly influence magnocellular neurons, suggesting that these blood borne peptides are detected in the SFO and AV3V and that they are acting as a neurotransmitter or a neuromodulator in the central nervous system to regulate water homeostasis.
ISSN 09149465
Learning Resource Type Article
Publisher Date 1989-01-01
e-ISSN 13491717
Journal Archives of Histology and Cytology(aohc1988)
Volume Number 52
Issue Number Supplement
Page Count 7
Starting Page 121
Ending Page 127


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