New method for evaluating intestinal contractions in guinea pig by curve fitting.

Using a "hybrid logistic function," we attempted to develop a new approach for a quantitative and comprehensive evaluation of the force-time curve of guinea pig gut contractions. We recorded ileum twitch and proximal colon spontaneous isometric longitudinal contractions because of their high regularities. We digitized the force-time curves of both contractions and performed curve fitting to them by hybrid logistic functions with a personal computer. We found that the fitness of these functions to both contractions was excellent. The respective best-fit parameters of these functions were closely correlated with the observed mechanical indexes, all of which are physiologically meaningful. This result suggests the possibility that these parameters can characterize the magnitudes and time courses of F(t) curves of the intestinal contractions. Furthermore, it might be able to show an effect of a pharmacological agent specifically either on the contraction phase, the relaxation phase, or other parameters of each. Therefore, we insisted that the present new approach for evaluating gut motility is promising for clinical application.