Short Term Effects of Endothelins on Tyrosine Hydroxylase Activity and Expression in the Olfactory Bulb of Normotensive Rat.

SABRINA L. NABHEN; GUADALUPE PERFUME; MARÍA A. BATTISTONE; ANDRÉS HUGO ROSSI; TAMARA ABRAMOFF; LILIANA G. BIANCIOTTI; MARCELO S. VATTA

NEUROCHEMICAL RESEARCH

Springer

Lugar: New York; Año: 2009 vol. 34 p. 953 - 963

0364-3190

<!-- @page { margin: 2cm } P { margin-bottom: 0.21cm } --> The olfactory system in rats is part of the limbic region with extensive afferent connections with brain areas involved in the regulation of behaviour and autonomic responses. The existence of the endothelin system and catecholaminergic neurons in the olfactory bulb suggests that endothelins may modulate noradrenergic transmission and diverse olfactory mediated processes. In the present work we studied the effect of endothelin-1 and -3 on neuronal norepinephrine release and the short-term regulation of tyrosine hydroxylase in the olfactory bulb. Results showed that both endothelins increased tyrosine hydroxylase activity through the activation of a non conventional endothelin G-protein coupled receptor, which in turn stimulated protein kinase A and C, as well as Ca2+/calmodulin-dependent protein kinase II. On the other hand, neither endothelin-1 nor endothelin-3 modified tyrosine hydroxylase total level, but both peptides increased the phosphorylation of serine residues of the enzyme at sites 19 and 40. Furthermore, endothelins enhanced norepinephrine release in olfactory neurons suggesting that this event may contribute to increased tyrosine hydroxylase activity by reducing feedback inhibition. Taken together present findings show a clear interaction between the endothelin system, and the catecholaminergic transmission in the olfactory bulb. Additional studies are required to evaluate the physiological functions regulated by endothelins at this brain level.