In vitro effect of tamsulosin and alfuzosin on the phasic, tonic, and spikes components of the response to NA in the epididymal and in the prostatic portion of rat vas deferens Tissue preparations were exposed to increasing concentrations of NA (10, 100, and 1000 μM) in the absence (vehicle) and in the presence of tamsulosin (10 nM) or alfuzosin (30 nM). The phasic response was measured as the distance between the baseline and the highest point reached at the initial contraction. The tonic response was measured as the mean distance between the baseline and the lowest spike in the phase of stabilization, 3 to 15 min after the administration of NA. The amplitude of the spikes was evaluated at this time. All three parameters were expressed in millinewtons. The values represent mean ± S.E.M of 12 experiments. Statistical analyses were carried out using a two-way ANOVA followed by a Newman-Keuls post hoc test.
| Drugs Applied in Vitro | Phasic Component | Tonic Component | Spikes Amplitude | ||||||
|---|---|---|---|---|---|---|---|---|---|
| 10 μM | 100 μM | 1000 μM | 10 μM | 100 μM | 1000 μM | 10 μM | 100 μM | 1000 μM | |
| Epididymal portion | |||||||||
| Vehicle | 7.7. ± 0.0.7 | 11.9 ± 1.1 | 13.0 ± 0.8 | 1.6 ± 0.3 | 3.6 ± 0.4 | 4.0 ± 0.4 | 1.9 ± 0.4 | 2.3 ± 0.3 | 2.5 ± 0.4 |
| Tamsulosin | 1.1 ± 0.3** | 3.6 ± 0.5** | 10.8 ± 0.7 | 0.0 ± 0.1** | 1.1 ± 0.1** | 3.6 ± 0.4 | 0.4 ± 0.1* | 4.1 ± 0.5** | 5.6 ± 0.9** |
| Alfuzosin | 1.7 ± 0.3** | 6.0 ± 1.0** | 12.4 ± 1.3 | 0.1 ± 0.1** | 1.5 ± 0.5** | 3.8 ± 0.2 | 0.4 ± 0.1* | 0.6 ± 0.1*## | 2.2 ± 0.3## |
| Prostatic portion | |||||||||
| Vehicle | 2.6 ± 0.5 | 4.5 ± 0.4 | 5.5 ± 0.5 | 1.3 ± 0.2 | 4.8 ± 0.6 | 6.1 ± 0.7 | 1.6 ± 0.2 | 2.9 ± 0.5 | 5.1 ± 1.0 |
| Tamsulosin | 0.4 ± 0.1** | 0.5 ± 0.1** | 0.5 ± 0.1** | 0.1 ± 0.1** | 0.1 ± 0.1** | 0.7 ± 0.1** | 0.6 ± 0.1* | 16.6 ± 2.8** | 28.5 ± 3.6** |
| Alfuzosin | 0.7 ± 0.1** | 1.7 ± 0.1** | 2.4 ± 0.4**# | 0.1 ± 0.1** | 1.7 ± 0.4**## | 3.7 ± 0.2**## | 1.0 ± 0.1* | 1.9 ± 0.5*## | 2.6 ± 0.6*## |