The role of pressure in the periodical changes of cardiac action in the fresh water mussel (Anodonta cygnea L.)

Pécsi, Tibor and Salánki, János (1964) The role of pressure in the periodical changes of cardiac action in the fresh water mussel (Anodonta cygnea L.). A Magyar Tudományos Akadémia Tihanyi Biológiai Kutatóintézetének évkönyve, 31. pp. 65-76. ISSN 0365-3005

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Abstract

The dependence of the heart frequency of the fresh water mussel (Anodonta cygnea L.) on changes of pressure connected with the periodical activity was investigated. Examinations were conducted on hearts in situ. For comparison also the effect of pressure changes on the isolated heart was studied. It has been established that the opening of the shells has a positive while their closure a negative chronotropic and inotropic effect on the heart in situ. Changes of pressure brought forth in the course of experiments on the isolated heart influenced the frequency of the pulsation of the heart in a very similar way. The change of frequency that could be observed in situ in the majority of cases appeared a few minutes earlier than the change observed in the position of the shells. This phenomenon could not be completely explained with mechanical effects accompanying the movement of the shells. It seems probable that from the visceral ganglion at the same time with the nerve impulse progressing to the posterior adductor muscle an excitation runs also to the heart which as to its effect somewhat precedes in time the response of the posterior adductor muscle.

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