<P> A neurohormone is any hormone produced and released by neuroendocrine cells (also called neurosecretory cells) into the blood . By definition of being hormones, they are secreted into the circulation for systemic effect, but they can also have a role of neurotransmitter or other roles such as autocrine (self) or paracrine (local) messenger . </P> <P> The hypothalamus produces releasing hormones and neurohypophysial hormones in specialized hypothalamic neurons which extend to the median eminence and posterior pituitary . The adrenal medulla produces adrenomedullary hormones in chromaffin cells, cells which are very similar in structure to post-synaptic sympathetic neurons, even though they are not neurons they are derivatives of the neural crest . </P> <P> Enterochromaffin and enterochromaffin - like cells, both being enteroendocrine cells, are also considered neuroendocrine cells due to their structural and functional similarity to chromaffin cells, although they are not derivatives of the neural crest . Other neuroendocrine cells are scattered throughout the body . </P>

Chemical signals released into the blood by neurons are called neurohormones