H7 modulation of the L3 auditory neuron and phonotaxis in the cricket Acheta domesticus

Several studies have implicated the L3 auditory interneuron in the regulation of syllable period selective phonotaxis in female cricket Acheta domesticus. The L3's response to model calls of conspecific males comprises of an immediate and a prolonged response. The kinetics of activation of these electrical activities are consistent with sequential activation of ionotropic and metabotropic mechanisms. In this study, we used electrophysiological and pharmacological tools to investigate the cellular mechanisms underlying L3's response. Bath application of the synthetic protein kinase inhibitor 1-(5-isoquinolinesul-fonyl)-2-methylpiperazine (H7), results in the suppression of L3's spiking response, and this effect can be reversed by saline wash. Additionally, when female A. domesticus that were previously nano-injected with H7 were tested for phonotaxis on a non-compensating treadmill, they demonstrated suppression of syllable period-dependent phonotaxis. These findings implicate protein kinase in the regulation of L3's spiking rhythm and the associated phonotaxis in A. domesticus.