Worm Breeder's Gazette 8(3): 46

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.

Gaba-Like Immounoreactivity in C. elegans Neurons

S. McIntire, R. Horvitz

Using anti-GABA antisera, we have identified possible GABAnergic 
neurons in C.  elegans.  The ventral and dorsal nerve cords, a series 
of commissures, and a number of cell bodies of the ventral nervous 
system stain with this antibody.  Swellings are often visible along 
the commissures near the region of the sublateral nerve cords, 
suggesting that synapses might be present.  The number and locations 
of these cells and processes indicate that they may be the DD and VD 
motorneurons.  These neurons correspond anatomically to the D1 and V1 
motorneurons of Ascaris, which Johnson et al.  have shown to have GABA-
like immunoreactivity (Newsletter, Vol.  8 No.  2).
We have also observed staining in both the heads and tails of C.  
elegans hermaphrodites and males.  The most striking staining in the 
head is a set of four neurons immediately anterior to the nerve ring; 
we have tentatively assigned these cells to be the RME neurons.  (Four 
cells resembling the RME neurons of C.  elegans have been found by 
Johnson et al.  to be GABA-positive in Ascaris.) The head neurons 
posterior to the nerve ring and the neurons in the tail remain to be 
In our staining protocol, animals were fixed overnight in 4% 
paraformaldehyde/1% glutaraldehyde and then permeablized by sequential 
treatment with elastase and collagenase.  (This technique allows 
adequate antibody penetration through the cuticle for wholemount 
staining.) Animals were then incubated first with a rabbit-anti-GABA 
primary antiserum, second with a goat-anti-rabbit IgG secondary 
antiserum, and third with a peroxidase-(rabbit) anti-peroxidase 
complex (PAP technique).  The chromogen diaminobenzidine then served 
as the substrate for the peroxidase and produced a colored reaction 
product allowing localization of cross-reactive substances.  We have 
also found that a fluorescent secondary antibody gives similar results.