Table S1.

Bioelectric parameters of microvessels isolated from control rat retinas and the suprahyperpolarized complexes of isolated ROP vessels in the absence or presence of the antioxidant NAC

Electrophysiological parameter	Control vessels	ROP complexes	ROP complexes in NAC
KATP conductance, pS	22 ± 26	1035 ± 280	190 ± 125
	n = 19	n = 8; P < 0.0001	n = 6: P < 0.0001
Non-KATP K+ conductance, pS	1,740 ± 525	1,790 ± 575	1,590 ± 505
	n = 19	n = 8; NS	n = 6; NS
NCX conductance, pS	450 ± 150	560 ± 180	460 ± 280
	n = 17	n = 12: NS	n = 8; NS
Equilibrium potential for NCX, mV	−32 ± 8	−103 ± 11	−88 ± 11
	n = 17	n = 12; P < 0.0001	n = 11; NS
NSC conductance, pS	1,350 ± 250	200 ± 235	440 ± 265
	n = 11	n = 9; P < 0.0001	n = 6; NS
Na+/K+ pump current, pA	22 ± 6	15 ± 8	13 ± 10
	n = 12	n = 5; NS	n = 4; NS
Resting membrane potential, mV	−45 ± 9	−92 ± 15	−84 ± 11
	n = 114	n = 87; P < 0.0001	n = 19; NS
Membrane capacitance, pF	250 ± 95	325 ± 170	275 ± 105
	n = 21	n = 5; NS	n = 5; NS
Membrane resistance, MΩ	350 ± 110	275 ± 220	420 ± 210
	n = 114	n = 87; NS	n = 19; NS

Glibenclamide (500 nM), ouabain (1 mM), and OMR-10103 (5 μM) were used to inhibit ATP-sensitive potassium (K_ATP) channels, the sodium/potassium pump, and the sodium/calcium exchangers, respectively. In experiments using n-acetyl cysteine (NAC), vessels were exposed to 100 µM of this antioxidant in the bathing solution at room temperature for 2.5–3.5 h before recordings were obtained in the NAC-supplemented solution. To assess the effect of the various pharmacologic inhibitors on vascular currents, negative-to-positive voltage ramps (50 mV·s⁻¹) were used to generate current-voltage (I-V) plots at 10-s intervals before and during exposure to a pharmacologic inhibitor. To determine the I-V relations of an inhibitor-sensitive current, the I-V plot generated ∼3 min after the onset of exposure to the inhibitor was subtracted from the I-V plot obtained before addition of the inhibitor. K_ATP conductances were determined between E_K and E_NSC. The Na⁺/K⁺ pump current at −50 mV is listed. The nonspecific cation (NSC) conductance was calculated between E_NSC and E_K by subtracting the ouabain-sensitive current and the OMR-10103–sensitive current from the total current measured at E_K. The non-K_ATP potassium conductance between E_NSC and E_K was calculated by measuring the total current at E_NSC and subtracting the glibenclamide-, ouabain- and OMR-10103–sensitive currents. Using current records filtered at 10 kHz, the membrane capacitance was determined from the transient charge induced by a 10- or 20-mV hyperpolarization from a holding potential of −58 mV, as described previously (36). Membrane resistance was calculated using the difference in the total currents measured at −100 mV and 0 mV in the absence of inhibitors. P values listed in the ROP complex column are for comparisons with control vessels; P values for the parameters in the NAC-treated group are for comparisons with the ROP complexes not exposed to the antioxidant. NS, not statistically significant. Of note, the relative hyperpolarizing influence of K_ATP channels, NSC channels, and NCX in the ROP complexes at a voltage of -45 mV were 0.4, 0.4, and 0.2, respectively.