THE DISTRIBUTION OF GLUTAMATE-LIKE IMMUNOREACTIVITY IN THE THORACIC AND ABDOMINAL GANGLIA OF THE LOCUST (SCHISTOCERCA-GREGARIA)

The distribution of glutamate-like immunoreactivity in the thoracic an d abdominal ganglia of the locust was studied using two polyclonal ant ibodies against glutamate. Because glutamate is a precursor of the inh ibitory transmitter gamma-amino butyric acid (GABA) the distribution o f immunostaining by antibodies against glutamate and GABA was closely compared in adjacent serial sections. When the antibodies were used at optimal dilutions there was no overlap in the distribution of immunos taining for glutamate and GABA. In the pro- and mesothoracic ganglia 3 60-400 somata are immunoreactive for glutamate, while in the metathora cic ganglion about 600 somata were stained. These range in diameter fr om 10-100 mum in diameter and include the majority of the large somata in these ganglia. Bundles of primary neurites emerging from these lar ge somata can be traced through the neuropile. Most of the bundles cor respond to the known paths of motor neurone primary neurites. In addit ion the 'T'-tract is also immunolabelled. The free abdominal ganglia e ach contain 80-100 somata ranging in size from 10-45 mum while the ter minal ganglion contains about 250 somata, 10-60 mum in diameter.