Neurohypophysial hormones and brain function: The neurophysiological effects of oxytocin and vasopressin

An increasing body of evidence suggests that the neurohypophysial hormones, in addition to their classical actions, may also act as neurotransmitters. They have a wide-spread but discontinuous distribution in the CNS; apart from their presence in the magnocellular nuclei they may be found in the hippocampus, amygdala, septum, substantia nigra, brainstem and spinal cord. They exert profound effects on behavior, particularly on memory, a function frequently ascribed to the hippocampus, amygdala and septum; on memory consolidation, internal reward and self stimulation functions frequently ascribed to brainstem and diencephalic aminergic systems including the substantia nigra and on sensory and autonomic responses which involve the medulla and spinal cord. When applied to the CNS they alter multiple unit activity in certain regions, particularly the hippocampus and cells which contain neural lobe hormones appear to be able to drive other cells synaptically. Finally application of the hormones can profoundly affect the activity of single nerve cells in just those parts of the CNS where, on the basis of their behavioral actions, they might be expected to act.