ABUNDANT DISTRIBUTION OF LOCUSTATACHYKININ-LIKE PEPTIDE IN THE NERVOUS-SYSTEM AND INTESTINE OF THE COCKROACH LEUCOPHAEA-MADERAE

An antiserum raised to the locust neuropeptide locustatachykinin I (Lo mTK I) was used for analysis of the distribution of tachykinin-related peptide in the cockroach Leucophaea maderae. Extracts of dissected br ains, suboesophageal ganglia, thoracic ganglia and midguts were separa ted by high performance liquid chromatography and the fractions analys ed in enzyme-linked immunosorbent assay with use of the LomTK antiseru m. Each of the tissues was found to contain LomTK-like immunoreactive (LomTK-LI) components with retention times corresponding approximately to synthetic LomTK I and II and callitachykinins I and II. The LomTK antiserum was also used for immunocytochemical mapping of peptide in t he nervous system and intestine oft. maderae. A large number of LomTK- LI interneurons were detected in the proto-, deuto- and tritocerebrum of the brain and in the suboesophaegeal ganglion. The immunoreactive n eurons supply processes to most parts of the brain: the central body, protocerebral bridge, mushroom body calyces, antennal lobes, optic lob e and most regions of the non-glomerular neuropil. A few protocerebral neurons send LomTK-LI processes to the glandular lobe of the corpora cardiaca. In each of the thoracic ganglia there are six LomTK-LI inter neurons and in each of the unfused abdominal ones there are two intern eurons. The fused terminal ganglion contains some additional cell bodi es in the posterior neuromers. LomTK-LI cell bodies were detected in t he frontal ganglion and fibres were seen in this ganglion as well as i n the hypocerebral ganglion. The frontal ganglion supplies LomTK-LI pr ocesses to the muscle layer of the pharynx. The muscle layer of the mi dgut is innervated by LomTK-LI fibres from the stomatogastric system ( oesophageal nerve and associated ganglia). Additionally the midgut con tains numerous LomTK-LI endocrine cells. A number of the pharyngeal di lator muscles were also found to be innervated by LomTK-LI fibres, pro bably derived from cell bodies in the suboesophageal ganglion. All the LomTK-LI neurons of the central nervous system appear to be interneur ons, suggesting a neuromodulatory role of the endogenous tachykinins. The tachykinin-like peptides from peripheral ganglia may be involved i n the control of foregut and midgut contractility and possibly the pep tide of the endocrine cells in the midgut has additional actions relat ed to intestinal function.