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. 2009 Oct 7;102(6):3573–3595. doi: 10.1152/jn.90732.2008

Fig. 1.

Fig. 1.

Bath application of the tyrosine kinase inhibitor genistein blocks in vitro conditioning-produced cumulative depolarization of type B photoreceptors. A: nervous system preparation and in vitro conditioning protocol. Simultaneous intracellular recordings from a type B photoreceptor (using microelectrode #2; ME2) and an ipsilateral caudal hair cell (ME1) were obtained. Following an initial 10 min of dark adaptation, 5 pairings of 30 s of light with 30 s of intracellular current stimulation of the hair cell were administered, at 2-min intervals. B: light stimulation of a type B photoreceptor (bottom trace) paired with depolarizing current stimulation of a caudal statocyst hair cell (top trace) results in a nearly 9-mV depolarization of the B cell. Hair cell stimulation elicited a high frequency train of action potentials, followed by a transient afterhyperpolarization (AHP) and reduction in spiking below the initial baseline level. Whole-field visual stimulation of the photoreceptor resulted in a sustained depolarizing generator potential and superimposed spiking in the type B cell. Dashed line underneath the type B photoreceptor record indicates the original baseline membrane potential of the B cell; the arrow indicates the 30-s time point following trial 5. This preparation was bathed in a 0.3% dimethyl sulfoxide (DMSO) artificial seawater (ASW). C: with 100 μM genistein in the bath, pairings of light and hair cell stimulation (not shown) resulted in a small hyperpolarization (∼1–2 mV) of this B cell, measured 30 s after trial 5 (arrow). The light response and spiking of the type B photoreceptor were not conspicuously affected by genistein, although genistein-treated cells generally showed a reduced long-lasting depolarization (LLD) response following light offset. D: summary data for B cells conditioned in the presence or the absence of bath-applied genistein. Depolarization was measured 2 min following the 5th conditioning trial. Cells exposed to genistein exhibited significantly less conditioning-produced cumulative depolarization than that of cells exposed to the DMSO bath solution. Error bars in this and all subsequent figures = ±SE.