Reduced [3H]-tetrodotoxin binding in the napts paralytic mutant of Drosophila. 
The temperature-sensitive paralytic mutant of Drosophila, napts, has been shown to have defects in axonal physiology which suggest that it codes for a component of the voltage-sensitive sodium channel.  Ligand binding studies using tritiated tetrodotoxin, a sodium channel antagonist, show a decrease in the apparent number of sodium channels in napts, providing additional support for this hypothesis.