Journal of Neuroscience, Vol 5, 992-1004, Copyright © 1985 by Society for Neuroscience
The distribution of a peptide neurotransmitter in the postembryonic grasshopper central nervous system
H Keshishian and M O'Shea
Proctolin is a peptide neurotransmitter, discovered in the visceral muscles
of the cockroach. The peptide has recently been identified in the nervous
systems of many invertebrates. Using reverse phase high pressure liquid
chromatography together with a sensitive bioassay, we analyzed the
distribution of proctolin in the central nervous system of the grasshopper
Schistocerca nitens. We also used immunocytochemistry to identify about 70
diverse proctolin-staining neurons in the postembryonic ventral nerve cord.
Proctolin immunoreactivity is rare, being found in only about 0.6% of the
ganglionic neurons. Among the cells we stained for proctolin were thoracic
skeletal motoneurons, a cluster of efferents to the intrinsic muscles of
the hindgut, and both inter- and intraganglionic thoracic interneurons, as
well as several interspecies homologues to proctolin-staining neurons in
the cockroach. The map of proctolin expression within the central nervous
system is not extensively altered during postembryonic life. It is the
product of embryonic development, which is the subject of the following
paper (Keshishian, H., and M. O'Shea (1985) J. Neurosci. 5: 1005-1015).