Worm Breeder's Gazette 8(2): 33
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.
Antiserum from: Tim Kingan and Sally Hoskins, Columbia University Idea from: Ed Hedgecock, MRC and Roche Institute of Mol. Biol. We have used an antiserum prepared against GABA conjugated with glutaraldehyde to BSA (see Storm-Mathisen, Nature 301, 517-520 for method) to localize GABA within the Ascaris nervous system. Preparations used for staining were collagenased to remove muscle cells (see Gazette 7(2), p54), fixed immediately with 2% glutaraldehyde, 0.5% formaldehyde for 1 hr, washed and treated with 1% ethanolamine, then 3% H2O2/10% methanol before incubation with serum ( overnight at 4 C). Antibody binding was detected using goat-alpha- rabbit conjugated to HRP and peroxidase-anti-peroxidase followed by staining for HRP using the DAB method. All of the commissures of VI and DI motorneurons stain intensely, whereas none of the DE1, DE2 or DE3 commissures stain. One interesting and unexpected feature of the inhibitory motorneuron commissures which the staining revealed, was the consistent occurrence of a short branch located in one of the sublateral nerve cords. Each commissure crosses both a (right or left) dorsal sublateral and a ventral sublateral nerve cord; VI commissures consistently have branches in the dorsal sublateral cord, while DI commissures have branches in the ventral sublateral cord. The function of this branch is unclear. Within the dorsal and ventral nerve cords, the processes of the inhibitory motorneurons are also intensely stained; there is no observable difference in the intensity of staining of dendritic and axonal regions of the neurons. We have also examined staining in the ganglia which surround the nerve ring (NR). Four large GABA-positive cell bodies are located at the margin of the NR: two are lateral, one ventral, one dorsal. The ventral and dorsal cells send a strongly staining process posteriorly in their respective nerve cords. All four cells have larger processes in the NR. These cells resemble the RME (V,D,L,R) neurons of C. elegans.There are two small intensely staining cells with cell bodies located in the left and right posterior lateral ganglia. These cells send a thin process in the deirid commissure to the ventral cord where they turn anteriorly, pass through the ventral ganglia and enter the NR. A likely homologue for these cells in C. elegans is RMG (L and R) . Finally, there is a pair of stained cell bodies in the ventral ganglia and another pair in the anterior lateral ganglia. We also find a single stained process in the anterior part of each of the four posterior sub-lateral nerve cords. Although we are not completely convinced that these sublateral processes are connected to these latter 4 cell bodies, we think that these cells may be equivalent to the SIB (VL,VR,DL and DR) neurons of C. elegans. A less consistent feature has been light staining of a pair of large cell bodies in the anterior lateral ganglia. Whether this is due to endogenous peroxidase activity or low levels of GABA-like immunoreactivity remains to be determined.