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Autoradiographic evidence for pathways from the medial preoptic area to the midbrain involved in the drinking response to angiotensin II
Author(s) -
Swanson L. W.,
Kucharczyk J.,
Mogenson G. J.
Publication year - 1978
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.901780404
Subject(s) - subfornical organ , ventral tegmental area , preoptic area , medial forebrain bundle , forebrain , biology , habenula , diencephalon , third ventricle , mammillary body , hypothalamus , lateral hypothalamus , midbrain , endocrinology , lateral parabrachial nucleus , amygdala , medicine , tegmentum , anatomy , efferent , angiotensin ii , central nervous system , parabrachial nucleus , striatum , dopamine , dopaminergic , blood pressure , afferent
The 3 H‐amino acid autoradiographic method was used to localize intracerebral sites from which angiotensin II (AII) elicits drinking and to identify their efferent neural pathways. Small injections (0.02‐0.1 μl) of AII and 3 H‐amino acid mixtures were injected together or separately into widespread regions of the forebrain of adult rats in normal food and water balance. From an analysis of 39 positive and negative injection sites it was concluded that the caudal half of the medial preoptic area and the adjacent rostral part of the anterior hypothalamic area are sensitive to AII. Two anatomically defined pathways arising from neurons within this region were identified. One descends through the medial forebrain bundle and appears to terminate in the lateral hypothalamic area, the ventromedial nucleus, the mammillary body, and the ventral tegmental area. The other descends through the periventricular region and posterior hypothalamic area to end in the midbrain central gray. Additional widespread connections with the amygdala, septum, habenula, and pons appear to arise in the lateral preoptic area (Swanson, '76). Combined AII‐ 3 H‐amino acid injections centered in the subfornical organ only elicited drinking in those cases in which injected label diffused through the third ventricle to the medial preoptic area. No efferent pathways were identified in experiments in which a small injection (0.02 μl) heavily labeled cells strictly confined to the subfornical organ and there was no ventricular spread of label.