neurosecretory

Neurosecretory describes cells and processes in which neurons release chemical messengers, often called neurohormones, into extracellular spaces or the bloodstream. Unlike conventional synaptic transmission, neurosecretory secretion coordinates endocrine and autonomic functions by delivering peptide or small molecule hormones that act distally on target tissues.

Neurosecretory cells are commonly located in the brain, particularly in the hypothalamus. Their axon terminals may terminate in the posterior pituitary, where stored neurohormones such as vasopressin (antidiuretic hormone) and oxytocin are released into the bloodstream. Alternatively, hypothalamic neurons release releasing or inhibiting hormones into the hypophyseal portal system, regulating the anterior pituitary.

Typical neurohormones include vasopressin, oxytocin, and hypothalamic releasing factors such as corticotropin-releasing hormone, thyrotropin-releasing hormone, gonadotropin-releasing hormone, growth hormone-releasing hormone, and somatostatin. These substances are synthesized in neuronal cell bodies, transported to axon terminals, and released in response to neural activity, often in a calcium-dependent manner via secretory vesicles.

Neurosecretory signaling is a widespread feature across animals, providing a mechanism for neurons to exert lasting endocrine effects. It differs from fast synaptic transmission in duration and systemic reach, but both systems can operate in concert within centralized neuroendocrine axes.