Fig. 7.

ScTx1 increases spontaneous phasic contraction amplitude, muscle force integral, and muscle tone in guinea pig DSM strips. A: representative original trace of spontaneous phasic DSM contractions and the effect of 100 nM ScTx1. B: summary data showing a statistically significant increase in DSM spontaneous phasic contraction amplitude, muscle force integral, and muscle tone. For comparison of the phasic contraction parameters of the DSM strips, data were normalized to the spontaneous contractions, which were taken to be 100%, and then expressed as percentages. DSM force is presented as muscle force integral and was determined by integrating the area under the curve of the phasic contractions component. The tone of the DSM strips was determined by measuring the phasic contraction baseline curve. To evaluate the effect of the ScTx1 on the phasic contractions, we analyzed a 5-min period before ScTx1 application for the controls and another 5-min period 30 min after ScTx1 application (100 nM). Values are means ± SE (n = 13; N = 7). *P < 0.05; **P < 0.01. Tetrodotoxin (1 μM) was present throughout the experiments.