Table 1.

Carbacholine-induced alteration to intracellular Na⁺ and K⁺ contents, total and ouabain-sensitive ⁸⁶Rb⁺ uptake

		Carbacholine incubation
	Control	10 min	60 min	60 min + salbutamol
Na+ content (μmol (g wet weight)−1)	15.2 ± 0.2	20.8 ± 0.3*	18.8 ± 0.7*	15.1 ± 0.4†
K+ content (μmol (g wet weight)−1)	87.7 ± 0.8	81.5 ± 1.0*	81.0 ± 1.3*	86.2 ± 0.4†
Total 86Rb+ uptake (nmol (g wet weight)−1 min−1)	514 ± 13	581 ± 8*	523 ± 16	704 ± 13*†
Ouabain-sensitive 86Rb+ uptake (nmol (g wet weight)−1 min−1)	296 ± 9	404 ± 12*	323 ± 16	516 ± 12*†

Muscles were mounted for isometric contraction and incubated with or without 10⁻⁴m carbacholine for 10 or 60 min ±salbutamol, with the final 10 min in the presence of ⁸⁶Rb⁺. After incubation, the muscles were washed for 4 × 15 min in ice-cold Na⁺-free Tris-sucrose, blotted, weighed, and prepared for flame photometric analysis of Na⁺ and K⁺ contents and counting of ⁸⁶Rb⁺. All values are given as means ± s.e.m. (n = 6–9).

^*Significant difference (P < 0.05) compared with control;

^†significant difference (P < 0.05) compared with 60 min carbacholine incubation.