Table 3. Effect of preincubation with tetrodotoxin (TTX, 0.1μmol/L) or 6-hydroxydopamine (6-OHDA, 1.46 mmol/L) on the frequency—contraction curves performed in mesenteric segments of control and pregnant rats.
| 1 Hz | 2 Hz | 4 Hz | 8 Hz | |
|---|---|---|---|---|
| Control | 21.31±2.23 | 34.10±2.56 | 52.41±2.22 | 69.28±3.91 |
| TTX | 0 | 0 | 0 | 0.5±0.06 |
| 6-OHDA | 0 | 0 | 0.1±0.02 | 0.2±0.04 |
| Pregnant | 16.42±2.72 | 25.9±3.58 | 39.28±4.04 | 53.75±3.99 |
| TTX | 0 | 0 | 0 | 0.4±0.05 |
| 6-OHDA | 0 | 0 | 0.1±0.01 | 0.3±0.05 |
Results (means ± S.E.M.) are expressed as percentages of the response elicited by 75 mM KCl; zeros are used when contraction was not detected. n = 7 animals each group.