Anatomical and functional implications of corticotrophin ‐releasing hormone neurones in a septal nucleus of the avian brain: an emphasis on glial‐neuronal interaction via V1a receptors in vitro

Previously, we showed that corticotrophin‐releasing hormone immunoreactive (CRH‐IR) neurones in a septal structure are associated with stress and the hypothalamic‐pituitary‐adrenal axis in birds. In the present study, we focused upon CRH‐IR neurones located within the septal structure called the nucleus of the hippocampal commissure (NHpC). Immunocytochemical and gene expression analyses were used to identify the anatomical and functional characteristics of cells within the NHpC. A comparative morphometry analysis showed that CRH‐IR neurones in the NHpC were significantly larger than CRH‐IR parvocellular neurones in the paraventricular nucleus of the hypothalamus (PVN) and lateral bed nucleus of the stria terminalis. Furthermore, these large neurones in the NHpC usually have more than two processes, showing characteristics of multipolar neurones. Utilisation of an organotypic slice culture method enabled testing of how CRH‐IR neurones could be regulated within the NHpC. Similar to the PVN, CRH mRNA levels in the NHpC were increased following forskolin treatment. However, dexamethasone decreased forskolin‐induced CRH gene expression only in the PVN and not in the NHpC, indicating differential inhibitory mechanisms in the PVN and the NHpC of the avian brain. Moreover, immunocytochemical evidence also showed that CRH‐IR neurones reside in the NHpC along with the vasotocinergic system, comprising arginine vasotocin (AVT) nerve terminals and immunoreactive vaso...
Source: Journal of Neuroendocrinology - Category: Endocrinology Authors: Tags: ORIGINAL ARTICLE Source Type: research