Muscle co-ordination of the respiratory pump of the carp (Cyprinus Carpio L.).

Since the beginning of the eighteenth century investigators have attempted to understand the mechanism of the respiration of fishes. Some have studied the driving elements of the respiratory pumps, the muscles, and others have analysed the outcome of the pumping movements, i.e. the pressures developed in buccal and opercular cavities. In the latter category Hughes & Shelton (1957, 1958, 1962) extensively described the hydrodynamics of the respiratory pumps of some fish species, using electrical manometers with a fast response. Saunders (1961) also studied the pressure changes in the buccal and opercular cavities of fishes, but he made use of tambour manometers. After the studies on the muscle co-ordination of the respiratory system based upon anatomical data only (discussed in a previous article (Ballintijn, 1969 a)) a better insight has been gained as a result of extirpation experiments, which among others have been conducted by Henschel (1939, 1941) and Holmquist (1910). The extirpation method, however, still is not ideally suited for the problem, because the function of an extirpated element can be (and often is) taken over by another, thus suggesting that the extirpated part is unimportant. The electromyographic technique, because it makes possible the exact determination of the active period of many muscles at the same time without seriously interfering with the system under observation, is ideally suited for the study of movement co-ordination. Hughes & Shelton (1962) and Ballintijn (1965) used intramuscular electrodes for the analysis of the respiratory mechanism of fish. Since then more detailed studies on the muscle co-ordination of the trout (Ballintijn & Hughes, 1965) and of the dogfish (Hughes & Ballintijn, 1965) have been conducted. In the present investigation the respiratory mechanism of the carp is analysed using electromyography. It was started because an exact knowledge of the muscle coordination of the carp is necessary to explain the data of experiments on the central nervous respiratory system (Ballintijn, unpublished).