Calcitonin gene-related peptide-like immunoreactivity and its relation with neurotensin- and corticotropin-releasing hormone-like immunoreactive neurons in the bed nuclei of the stria terminalis in the rat.

The distribution of calcitonin gene-related peptide (CGRP)-like immunoreactive (LI) nerve cells and terminals (BST) was studied in the rat. Only the fusiform nucleus was found to consistently contain CGRP-LI neurons. The CRGP-LI terminals had a wide distribution in the BST, being most numerous in the oval and the fusiform nuclei. In the oval nucleus the CGRP-LI terminals formed characteristic "baskets." Since the oval nucleus was known to be studded with neurotensin (NT)- and corticotropin-releasing hormone (CRH)-LI neurons, the relationship of the CGRP-LI nerves to NT- and CRH-LI neurons was investigated by means of a double immunostaining technique. A part of the CGRP-LI baskets were found to contain NT- or CGRP-LI neurons. The possible involvement of the CGRP/NT or CRH relationship in reciprocal connection between the BST and the parabrachial nucleus and in cardiovascular regulation is discussed.