Localization of different releasing hormone immunoreactive (LH-IR) neurons and their projections in central nervous system of birds. A mini-review.

Abstract

The aim of the present review is to summarize the question of the co-existence of two or more releasing hormones within a neuron or nucleus of the avian central nervous system (CNS). Furthermore, we attempt to differentiate between the character and functional significance of hypothalamic and of extrahypothalamic releasing hormone containing neurons. In order to approach these important questions, we have to summarize the localization and distribution of the different releasing hormone immunoreactive (RH-IR) structures in the avian brain, compared to the much more thoroughly investigated mammalian releasing hormone system. This mini-review comprises data obtained by immunohistochemical approach, exclusively. Other data, based on radioimmunoassay or other morphological methods, will be omitted here.