Fig. 8: High BPA exposure at 7 dpf enhances I_K currents, but reduces I_Ca.

Whole-cell patch clamp techniques in the zebrafish retinal slice preparation were used to record voltage gated potassium (I_K) and calcium (I_Ca) currents of retinal bipolar cells. A Representative whole cell currents from vehicle (N = 4), low BPA (N = 5), and high BPA (N = 4) treated tissues. Responses were elicited from V_hold = −60 mV and in response to voltage steps from −80 to +60 mV in 10 mV increments. Brackets denote differences among treatments. B Current-voltage relationship depicting mean ( ± SE) current amplitudes at each voltage step. Differences were observed for voltage steps to −20 mV or higher (asterisks). Steps to −20 mV (p = 0.004) or −10 mV (p = 0.003) identified a difference between high BPA vs. vehicle controls. A voltage step to 0 mV (p = 0.005) showed differences between high BPA and all other treatment groups. Voltage steps to +10 mV or more depolarized levels (p < 0.004) revealed a difference between low vs. high BPA treatment groups. C Representative whole-cell Ca⁺² current elicited by a voltage step to −30 mV (V_hold = −60 mV), when the greatest amplitude differences were noted. Vehicle (N = 3), low BPA (N = 3), high BPA (N = 2). Whole cell Ca⁺² currents elicited by voltage steps from −50 to 0 mV in 10 mV increments from V_hold = −60 mV. D Current-voltage relation showing peak amplitude of the calcium current. Low and high BPA exposure reduced I_Ca amplitude.