Table 2.

Effect of carbachol upon enzymatic activities and PI turnover. Influence of enzymatic inhibitors

Additions	Phosphoinositide (area/mg)	PKC (pmol/min/ mg protein)	NOS (pmol/g tissue wet wt)
Basal	192±12	1.2±0.1	240±18
Carbachol	383±22*	5.8±0.3*	848±21*
Carbachol+U-73122	178±15*	1.5±0.1**	250±15**
Carbachol+Trifluoperazine	356±21	5.4±0.2	485±20**
Carbachol+Calphostin	422±35	1.1±0.1**	323±20**
Carbachol+L-NMMA	356±25	5.5±0.2**	198±15**

Abbreviations: L-NMMA, N^G-monomethyl-L-arginine; NOS, neuronal nitric oxide synthase; PKC, protein kinase C; PI, phosphoinositide; U-73122, 1-6-17β-3-methoxgestra-1,3,5 (10)-trien-17yl-aminohexyl-1-H-pyrrole-2,5-dione.

Values are mean±s.e.m. of five experiments in each group performed in duplicate. Enzyme activities were measured after incubation rat atria after 2 h in the presence of carbachol with or without enzyme inhibitors. Carbachol was used at 1 × 10⁻⁷ M and U73122 5 × 10⁻⁶ M, TFP 5 × 10⁻⁶ M, calphostin 5 × 10⁻⁹ M and L-NMMA 5 × 10⁻⁵ M.

^*P<0.001 comparing with basal values (no additions)

^**P<0.001 comparing with carbachol alone.