Calcitonin gene-related peptide (CGRP): immunocytochemical identification of a neuropeptide synthesised by ventral paraventricular magnocellular neurones in the sheep.
The distribution of calcitonin gene-related peptide (CGRP)-immunoreactive neurones was examined in the hypothalamus and pituitary gland of the short-term ovariectomised ewe. A large number of magnocellular CGRP-immunoreactive neurones were identified in the ventral paraventricular nuclei (PVN); few were found in the dorsal PVN and supraoptic nuclei. Parvicellular CGRP-immunoreactive neurones were identified in low density scattered throughout the preoptic region, anterior and basal hypothalamus and region of the stria terminalis. A dense CGRP innervation of the median eminence and neural lobe of the pituitary was observed. These observations reveal substantial species differences in CGRP immunoreactivity compared with the rat and show that magnocellular CGRP-synthesising neurones in the sheep are essentially restricted to, and define, the ventral PVN. This suggests a functionally distinct role for this previously neglected division of the PVN within the ovine hypothalamo-neurohypophyseal system.
PubMed Abstracts
PubMed Abstracts