Table 1.
Membrane potential and ACh-induced hyperpolarization in the guinea-pig coronary artery
| ACh-induced hyperpolarization (mV) | |||
|---|---|---|---|
| Condition | Membrane potential (mV) | Initial | Slow |
| Control (resting potential) | -51.5 ± 2.6 (31) | 20.5 ± 3.1 (31) | 4.9 ± 1.5 (31) |
| Indomethacin (5 × 10−6 M) | -50.5 ± 2.5 (10) | 20.1 ± 4.0 (10) | 0 (10) * |
| Diclofenac (10−6 M) | -51.5 ± 3.5 (11) | 19.5 ± 3.3 (11) | 0 (11) * |
| Nitroarginine (10−5 M) | -51.1 ± 3.8 (12) | 19.1 ± 4.0 (12) | 5.9 ± 1.8 (12) |
| Nitroarginine (10−5 M) + indomethacin (5 × 10−6 M) | -50.8 ± 2.8 (8) | 20.2 ± 3.8 (8) | 0 (8) * |
| SKF 525a (3 × 10−5 M) | -48.0 ± 4.8 (7)* | 2.5 ± 1.2 (10)* | 0.6 ± 0.5 (10)* |
| SKF 525a (10−4 M) | -43.7 ± 2.5 (10)* | 0.7 ± 0.7 (10)* | 0 (10)* |
| Clotrimazole (10−5 M) | -33.5 ± 1.7 (6)* | 2.5 ± 1.2 (6)* | 0.5 ± 0.1 (6)* |
| NDGA (10−5 M) | -49.3 ± 3.5 (8) | 21.5 ± 2.8 (8) | 5.2 ± 1.7 (8) |
| CTX (5 × 10−8 M) | -44.9 ± 2.5 (10)* | 2.5 ± 1.5 (10)* | 3.8 ± 1.5 (10)* |
| Apamin (10−7 M) | -48.8 ± 3.5 (7) | 16.5 ± 3.5 (7)* | 5.0 ± 2.0 (7) |
| Ba2+ (10−4 M) | -46.5 ± 3.0 (6)* | 22.2 ± 2.0 (6)* | 6.7 ± 1.5 (6)* |
| Ba2+ (10−3 M) | -38.5 ± 3.3 (7)* | 16.3 ± 2.1 (7)* | 1.7 ± 0.5 (7)* |
| Glibenclamide (10−6 M) | -43.3 ± 3.2 (12)* | 23.5 ± 2.5 (12)* | 0 (11)* |
Membrane potentials were measured after addition of individual drugs for over 5 min. ACh (10−6 M) was then applied for 1 min, and the peak amplitude of the initial and slow components of the hyperpolarization was measured from the potential before application of ACh. Values are means ±s.d. (number of observations).
*
P < 0.05, compared with control.