TABLE 1.

KCl-induced and ATP-induced changes in [Ca²⁺]_i in cardiomyocytes and sarcolemmal (SL) ATP binding in vitamin B₆ deficient rats.

Parameters	Control	Vitamin B6 deficient	Vitamin B6 treated
A. Cardiomyocytes [Ca2+]i
Basal [Ca2+]i, nM	121 ± 8.6	118 ± 4.4	123 ± 6.4
Increase in [Ca2+]i due to 30 mM to KCl, nM	86 ± 5.1	129 ± 8.1*	88 ± 5.5†
Increase in [Ca2+]i due to 100 μM ATP, nM	69 ± 4.7	33 ± 4.5*	64 ± 4.2†
Increase in [Ca2+]i due to 10 μM ATP, nM	37 ± 5.8	12 ± 3.6*	–
B. SL ATP binding
ATP binding at 2 nM ATP, pmol/μg protein	3.2 ± 0.25	2.3 ± 0.17*	–
ATP binding at 10 nM ATP, pmol/μg protein	14.0 ± 0.89	9.1 ± 1.2*	–

Control and vitamin B₆ deficient rats were fed vitamin B₆-containing or vitamin B₆-deficient diet for 8 weeks before isolating cardiomyocytes or sarcolemma from the heart. For vitamin B₆ treated group, 8 weeks vitamin B₆-deficient rats were injected pyridoxin hydrochloride (10 mg/kg; i.p.) 24 h before the experiment. The data are taken from our paper (Dakshinamurti et al., 1998). *P < 0.05 vs. control; ^†P < 0.05 vs. vitamin B₆ deficient group.