Anatomical evidence that neural circuits related to the subfornical organ contain angiotensin II.

Bidirectional connections between the subfornical organ and the hypothalamus are reviewed, and emphasis is placed on recent evidence for the presence of angiotensin II in some of these pathways. Additionally, evidence is presented suggesting that this peptide may serve as a neurotransmitter or neuroendocrine factor in the efferent projections of cell groups receiving neural inputs from the subfornical organ. It appears that angiotensin II may serve as one of the chemical messengers at each link in multi-synaptic pathways related to the subfornical organ.