Channel Model of Second Messenger Mediated Transformation of GABA Induced Currents

Hermissenda crassicornis exhibits Pavlovian conditioning in response to repeated presentations of paired light and turbulence stimuli. The behavioral changes are correlated with a change in electrical properties of the B photoreceptor cell. In response to turbulence, the hair cell releases GABA onto the terminal branches of the B cell. After repeated stimulation of the B cell using a light flash paired with GABA, the net GABA induced currents change from inhibitory to excitatory. To investigate the mechanisms underlying the change in GABA induced currents from net inhibitory to net excitatory, channel models of the GABA induced currents are developed. The similarity of measured and modeled currents supports the hypothesis that the transformation of GABA currents depends on second messenger mediated events such as phosphorylation.