Table 1.
Control values for changes in diastolic blood pressure induced electrically or chemically in pithed and vagotomized rats pretreated with pancuronium (0.8 μmol kg−1; i.v.)
| Changes in DBP | |||||
|---|---|---|---|---|---|
| Type of stimulation | Antagonist | Induced by S1 (mmHg) | S2/S1 | S3/S1 | S4/S1 |
| Electrical | No | 28±2 | 0.94±0.06 | 1.14±0.05 | 1.10±0.07 |
| SR 141716A 0.1 | 29±2 | 0.94±0.05 | 1.09±0.07 | 1.10±0.10 | |
| SR 144528 3 | 29±2 | 1.03±0.03 | 1.11±0.13 | 1.08±0.12 | |
| Capsazepine 1 | 33±4 | — | 0.94±0.04 | — | |
| Clobenpropit 0.1 | 29±2 | 1.08±0.03 | 1.09±0.06 | 1.10±0.08 | |
| Noradrenaline | No | 30±2 | 1.05±0.04 | 1.07±0.07 | 1.01±0.10 |
Up to four stimuli (S1–S4) were administered to pithed rats. An increase in blood pressure was induced by electrical stimulation (1 Hz, 1 ms, 50 V for 10 s) of the preganglionic sympathetic nerve fibers or by bolus injection of noradrenaline (1–3 nmol kg−1, i.v.). SR 141716A or SR 144528 was given 10 min, and pancuronium was administered alone or with clobenpropit 5 min, prior to S1. Capsazepine was injected i.v. 2 min prior to S1 and S3. Doses of the receptor antagonists are given in μmol kg−1. The alterations in DBP are given either as absolute values (for S1) or as ratios (relative to S1) for the three subsequent stimuli (S2, S3 and S4). Means±s.e.m. of 4–21 rats.