TYROSINE-HYDROXYLASE IN THE CEREBRAL GANGLIA OF THE AMERICAN COCKROACH (PERIPLANETA-AMERICANA L) - AN IMMUNOHISTOCHEMICAL STUDY

We have investigated the distribution of tyrosine-hydroxylase-like imm unoreactivity in the cerebral ganglia of the American cockroach, Perip laneta americana. Groups of tyrosine-hydroxylase-immunoreactive cell b odies occur in various parts of the three regions of the cerebral gang lia. In the protocerebrum, single large neurons or small groups of neu rons are located in the lateral neuropil, adjacent to the calyces, and in the dorsal portion of the pars intercerebralis. Small scattered ce ll bodies are found in the outer layers of the optic lobe, and cluster s of larger cell bodies can be found in the deutocerebrum, medial and later-al to the antennal glomeruli. Thick bundles of tyrosine-hydroxyl ase-positive nerve fibers traverse the neuropil in the proto- and deut ocerebrum and innervate the glomerular and the nonglomerular neuropil with fine varicose terminals. Dense terminal patterns are present in t he medulla and lobula of the optic lobe, the pars intercerebralis, the medial trito-cerebrum, and the area surrounding the antennal glomerul i, the central body and the mushroom bodies. The pattern of tyrosine-h ydroxylase-like immunoreactivity is similar to that previously describ ed for catecholaminergic neurons, but it is distinctly different from the distribution of histaminergic and serotonergic neurons.