Immunocytochemical demonstration of the presence of catecholamine and serotonin neurons in the sheep olfactory bulb

The catecholamine and serotonin innervation of the sheep olfactory bulb was studied using immunocytochemistry. Specific antisera raised against tyrosine hydroxylase, dopamine beta-hydroxylase, phenylethanolamineN-methyl transferase and serotonin were used. Tyrosine hydroxylase-positive cell bodies were present in all cell layers except in the anterior olfactory nucleus, the greatest number being found in the glomerular layer. Neither dopamine β -hydroxylase-positive nor serotonin-positive cell bodies were observed. Dopamine β-hydroxylase-positive fibers were widely distributed in the granule cell layer but less widely in other layers. The glomerular layer contained the greatest distribution of serotonergic positive fibers, but such fibres were also visualized in other cell layers. No phenylethanolamineN-methyl transferase-positive structures were found in this investigation.