Neuroendocrine anatomy of the hypothalamus

The hypothalamus is a most complex part of the CNS having rich interconnections with forebrain, limbic and brainstem structures. Its outflow is directed in such a way as to influence the endocrine system (via the neurohypophyseal and adenohypophyseal neurosecretory systems), the autonomic nervous system (via projections to preganglionic cell groups in brainstem and spinal cord) and behavioural responses to physiological and environmental cues via its interaction with limbic and somatomotor systems. The chemical identity of many of its neuronal messengers and those of some of its important afferents, such as the monoaminergic neurons, has opened the way to a form of systematic experimental investigation with chemical tools more powerful than those available to neuroendocrinologists in the past. Much of the information which follows has accrued very rapidly through the use of these methods to reveal the rich complexities of neuroendocrine integration.