Second messenger systems mediating sex pheromone and amino acid sensitivity in goldfish olfactory receptor neurons.

Teleost fish have three morphologically different types of olfactory receptor neurons (ORNs), ciliated, microvillous and crypt cells, which employ either adenylate cyclase (AC)/cyclic-AMP (cAMP) or phospholipase C (PLC)/inistol triphosphate (IP3) as second messenger systems (Sorensen and Caprio, 1998; Hansen et al., 2003). The chemical sensitivities and functions of these cell types are poorly understood. For example, EOG recording using forskolin and U71322 as adapting solutions has suggested that sensitivity to amino acids is mediated by at least two classes of neurons, one employing AC/cAMP, another PLC/IP3 (Rolen et al., 2002; Hansen et al., 2003). The present study used a combination of single-unit and EOG recording together with pharmacological agents to further elucidate the roles of AC and PLC pathways mediating responses to amino acid (food) odors and sex pheromones in goldfish ORNs.