1999 Volume 65 Issue 3 Pages 472-477
As a part of study programs on the rigor mortis progress in fishes, we tried to clarify the influence of pink muscle fiber in dorsal ordinary muscle on the rigor mortis progress. Muscle fiber types in dorsal ordinary muscle of several fishes were discriminated by inactivation of actomyosin ATPase after acid and alkaline preincubations, and rigor mortis with the lapse of time, was measured in the pillar form of dorsal muscle.
The pink muscle fiber was found in the ordinary muscle of many sample fishes and it was recognized in mosaic pattern among white muscle fibers. The muscle fiber types were found as follows: pink muscle fiber (P) and white muscle fibers (W) of Ha and lib like subtypes {P+W(IIa+IIb)}, pink muscle fiber and white muscle fiber of IIa or lIb like subtype {P+W(IIa or lIb)}, white muscle fibers of Ha and lIb like subtypes {W(IIa+IIb)}, and white muscle fiber of Ila or lIb like subtype {W(IIa or lIb)}. The rigor mortis progress in fishes organized from P+W(IIa+lIb) or P+W(IIa or lIb) were considerably higher in response to the maximum level reached than that in the fishes from W(IIa+lIb) or W(IIa or lib). This phenomenon was consistent in fishes composed of pink and white muscle fibers. Therefore, it was considered that the presence of the pink muscle fiber in the dorsal ordinary muscle might influence the rigor mortis progress.
