Subfornical organ-angiotensin II pressor system takes part in pressor response of emotional circuit.
It has been proved that there are the subfornical organ (SFO)-nucleus paraventricularis (NPV)-rostral ventrolateral medulla (RVL) angiotension II (AngII) pressor system and the central amygdaloid nucleus (AC)-lateral hypothalamus/perifornical region (LH/PF) emotional pressor system in the brain. Because the LH/PF contains abundant AngII ergic neurons projecting to the SFO, the purpose of the present study was to examine whether the (SFO-NPV-RVL) AngII pressor system takes part in the AC-pressor response via AngII ergic neurons in the LH/PF. The results showed that (1) L-glutamate microinjection into the AC or LH/PF induced pressor responses. (2) Both the AC- and LH/PF-pressor responses could be reversed by preinjection of [Sar(1), Thr(8)]-angiotensin II (an antagonist of AngII) into either the SFO, NPV or RVL. Taken together with our previous findings that the projections of the CRF-ergic and SP-ergic neurons in the AC could activate the LH/PF, the above findings prove that: besides several known mechanisms of the brain AngII inducing pressor response, the (SFO-NPV-RVL) AngII pressor system also takes part in the AC-emotional pressor response via AngII ergic projections from the LH/PF to the SFO, which may be the neurophysiological basis of the brain AngII playing an important role in developing hypertension of the SHRs.
D000679:Amygdala / Q000187:drug effects / Q000502:physiology; D000804:Angiotensin II / Q000037:antagonists & inhibitors / Q000494:pharmacology / Q000502:physiology*; D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D001921:Brain / Q000187:drug effects / Q000502:physiology*; D018698:Glutamic Acid / Q000494:pharmacology / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D006651:Histocytochemistry; D006973:Hypertension / Q000503:physiopathology; D007026:Hypothalamic Area, Lateral / Q000187:drug effects / Q000502:physiology; D020646:Intralaminar Thalamic Nuclei / Q000187:drug effects / Q000502:physiology; D008297:Male; D008845:Microinjections; D008959:Models, Neurological; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D013315:Stress, Psychological / Q000378:metabolism / Q000503:physiopathology*; D013356:Subfornical Organ / Q000187:drug effects / Q000502:physiology*
D000804:Angiotensin II; D018698:Glutamic Acid