Analysis of connexin (Cx36 and Cx45) expression in the carotid body, adrenal medulla and enteric neurons of both mouse and rat

Abstract

Cx36 and Cx45 are considered the main connexins expressed in neuronal cells of central nervous system (Belluardo N. et al. Brain Res. 2000)), but at present no complete data are available on their expression in the neurons of crest-derived neuroendocrine organ, such as the adrenal medulla, the carotid body and the enteric nervous system. Therefore the present study was undertaken to evaluate using immunohistochemistry and western blotting procedures, both in rat and mouse, whether Cx36 and Cx45 were expressed in neuronal cells of the carotid body, adrenal medulla and myenteric plexus at ileum and colon level. In the carotid body of both mouse and rat only Cx45 was found expressed as diffuse punctate immunostaining. High amount of Cx36 expression was detected in the medulla and zona glomerulosa of mouse adrenal gland, but not in the rat. The Cx45 was found only in the mouse zona reticularis of adrenal gland cortex. Very low amount of Cx36 punctate immunostaining was found in the myenteric plexus of mouse colon and ileum but not in the rat. No Cx45 immunostaining was evidenced in the myenteric plexus of both mouse and rat, although it was found along the circular muscle of colon and ileum. Using western blotting analysis we confirmed for both Cx36 and Cx45 the results obtained by immunohistochemistry. Taken together our data increase our insight into types of gap-junctions localized in neuronal of sympatho-adrenal system and their different expression between species.