Effects of each blocker on the chronotropic responses to PACAP-27 and VIP after atropine or atropine and propranolol treatment in autonomically decentralized hearts of the anesthetized dogs
| Drug | Changes in Sinus Rate (Beats/Min) | |
|---|---|---|
| Control | After drug treatment | |
| I. Atropine (0.7 μmol/kg i.v., n = 4) | ||
| ACh (3–10 nmol) | −69 ± 22.0 | 02-a |
| Propranolol (30 nmol i.a., n = 4) in the presence of atropine | ||
| PACAP-27 (0.1 nmol) | 46 ± 11.2 | 47 ± 11.0 |
| NE (0.3–1 nmol) | 39 ± 7.5 | 02-b |
| II. Atropine (0.7 μmol/kg i.v., n = 5) | ||
| ACh (3–10 nmol) | −93 ± 13.8 | 02-c |
| TTX (30 nmol i.a.,n = 5) in the presence of atropine | ||
| PACAP-27 (0.1 nmol) | 54 ± 8.1 (100%) | 35 ± 4.6 (65 ± 2%)2-c |
| Nicotine (10 nmol) | 32 ± 3.7 | 02-c |
| III. Atropine (0.7 μmol/kg i.v.) + propranolol (3.4 μmol/kg i.v.) (n = 4) | ||
| NE (0.3–1 nmol) | 72 ± 16.1 | 1 ± 1.02-b |
| ACh (3–10 nmol) | −57 ± 10.2 | 02-b |
| PACAP-(6–27) (10 nmol i.a., n = 4) in the presence of atropine and propranolol | ||
| PACAP-27 (0.1 nmol) | 59 ± 12.3 (100%) | 28 ± 3.7 (49 ± 4%)2-c |
| VIP (0.03 nmol) | 32 ± 2.9 (100%) | 35 ± 5.4 (109 ± 14%) |
| IV. Atropine (0.7 μmol/kg i.v.) + propranolol (3.4 μmol/kg i.v.) | ||
| NE (0.3–1 nmol) | 64 ± 6.9 | 02-c |
| ACh (3–10 nmol) | −38 ± 5.5 | 02-c |
| VIP-(10–27) (10 nmol i.a., n = 4) in the presence of atropine and propranolol | ||
| PACAP-27 (0.1 nmol) | 63 ± 7.9 (100%) | 51 ± 7.1 (85 ± 16%) |
| VIP (0.03 nmol) | 47 ± 2.0 (100%) | 16 ± 5.8 (34 ± 12%)2-b |