Physiological and chemical architecture of a lobster ganglion with particular reference to gamma-aminobutyrate and glutamate.

Abstract

The physiological organization of lobster ganglia has been correlated with certain chemical properties of excitatory and inhibitory neurons. Methods were developed for physiologically identifying and then isolating the cell bodies of efferent neurons. Gamma-aminobutyric acid (GABA) and glutamate contents of the cell bodies were assayed by enzymic methods. The physiological functions of 21 pairs of neurons were determined. The cell bodies occur in clusters which are constant in location and composition. Adjoining excitatory cells innervate the same or synergistic muscles. In contrast, the identified inhibitory cells are grouped together although they innervate muscles with different or opposing action. Certain cell bodies are so constant in size and position that they can be recognized with confidence by visual inspection alone. In conformity with previous studies on axons, GABA analysis revealed 2 populations of cell bodies; inhibitory cells with a high GABA content (the lower limit being about 0.014 [image]) and excitatory cells with a low GABA content (below the limit of accurate measurement with our assay). Glutamate is about equally concentrated in the 2 types of cell bodies.