Abstract
Action potentials (AP) N1, N2 and the excitatory postsynaptic potential-like response (EPSP-like) were recorded for auditory signals in Acheta domesticus (house cricket). Recordings were made from the fifth abdominal ganglion, the site of the first synapse of the cercal hearing system. Stimulus parameters were varied to formulate and optimum set of stimulus conditions that best elicited the evoked responses. For high intensity low frequency signals, APs were clearly visible. For low intensity signals the AP amplitude decreased leading to a broad, low-frequency wave identified as the EPSP-like response. Pharmacologic agents tetrodotoxin and kynurenic acid were used to differentiate the potentials. Tetrodotoxin reduced APs but had no effect on the EPSP-like response. Kynurenic acid brought about complete inhibition of all auditory evoked potentials. These results indicate that the cricket cercal hearing system can be used as a model to study auditory evoked potentials, and also suggests the possibility of the presence of excitatory amino acid receptors in the fifth abdominal ganglion of the house cricket.
