Table 1.
Descriptive summary of pharmacological actions and relative effects of receptor agonists or antagonists (of A1, A3, nicotinic, 5HT4, NK1, H2 receptors) or inhibitors on the dimaprit-induced stereotype cyclical coordination response in guinea pig distal colon
| Effect |
|||
|---|---|---|---|
| Drug | Receptor | Cyclic Crypt Cell Secretion (via ΔIsc) | Cyclic Contraction (via ΔICD) |
| Antagonist | |||
| CPT, 0.5 μM | A1 | 133% ↑ | 64% ↑ |
| PACPX, 0.1 μM | A1 | 160% ↑ | |
| FSCPX, 1.0 μM | A1 | 120% ↑ | |
| MRS1191, 1–10 μM | A3 | 130% ↑ | 110% ↑ |
| RS 39604, 10 μM | 5HT4 | 100% ↓ | 100% ↓ |
| Cimetidine, 10 μM | H2 | 100% ↓ | 100% ↓ |
| Mecamylamine, 10 μM | Nic-R | 100% ↓ | 100% ↓ |
| GR 82334, 1 μM | NK1-R | 60–95% ↓ | 100% ↓ |
| Inhibitors | |||
| Bumetenide | Na+Cl− cotransport | 100% ↓ | 0% ↓ |
| Basal secretion | Circular muscle tone | ||
| TTX, 0.1–0.25 μM | Na+ channels | 10% ↓ | 33% ↓ (relaxation) |
| TTX + IB-MECA | No effect | 52% ↓ (relaxation) | |
| Agonists | |||
| CCPA, 0.05 μM | A1 | 100% ↓ | 100% ↓ |
| IB-MECA, 1–10 μM (+FSCPX knockdown) | A3 | 100% ↓ | 100% ↓ |
ΔIsc, change in short-circuit current; ΔICD, change in intracrystal distance; CPT; 8-cyclopentyltheophylline; PACPX; 1,3-dipropyl-8-(2-amino-4-chlorophenyl)xanthine; FSCPX; 8-cyclopentyl-N3-[3-(4-(fluorosulfonyl)benzoyloxy)propyl]-N1-propylxanthine; MRS1191, 3-ethyl-5-benzyl-2-methyl-4-phenylethynyl-6-phenyl-1,4-(±)-dihydropyridine-3,5-dicarboxylate; RS 39604, 1-[4-amino-5-chloro-2-(3,5-dimethoxyphenyl)methyloxy]-3-[1-[2-methylsulfonylamino]ethyl]piperidin-4-yl]propan-1-one hydrochloride; Nic-R, nicotinic receptor; NK1, neurokinin-1; TTX, tetrodotoxin; IB-MECA, N6-(3-iodobenzyl)-adenosine-5′-N-methyluronamide; CCPA, 2-chloro-N6-cyclopentyladenosine.