ON THE RECEPTOR FUNCTION OF THE SWIM BLADDER OF FISHES

Size: px

Start display at page:

Download "ON THE RECEPTOR FUNCTION OF THE SWIM BLADDER OF FISHES"

Myles Jenkins
5 years ago
Views:

1 i6 ON THE RECEPTOR FUNCTION OF THE SWIM BLADDER OF FISHES BY CH. S. KOSHTOJANZ AND PH. D. VASSILENKO Section of Comparative Physiology, Timiriasev Biological Institute, Moscow {Received i April 1936) (With Five Text-figures) IN spite of extensive investigation of the function of the swim bladder of fishes, our knowledge of the physiological role of this organ is far from complete. Two functions are usually ascribed to the swim bladder, viz. a participation in the Fig. 1. i, registration of respiratory movements; 2, registration of heart contractions; 3, registration of movements of fin; 4, registration of movements of tail; 5, rubber tube, supplying water to gills; 6, N. n. vago-sympathici; 7, direction of operational cut; 8, rubber balloon for increasing pressure in swimming bladder; 9, manometer; io, induction coil. co-ordination of the movements of fishes, and a participation in the act of breathing. Recent research has made it evident that the secretion of gas by those fishes which possess a red body in their bladder and the introduction of air into the bladder of those which have no red body provide stimuli which are capable of modifying

2 JOURNAL OF EXPERIMENTAL BIOLOGY, XIV, i. PLATE I r HELFF STUDIES ON AMPHIBIAN METAMORPHOSIS (pp. i 15)

4 JOURNAL OF EXPERIMENTAL BIOLOGY, XIV, i. PLATE II 4 N HELFF STUDIES ON AMPHIBIAN METAMORPHOSIS (pp. i 15)

6 On the Receptor Function of the Swim Bladder of Fishes 17 to a marked degree the locomotory responses of the animals. The present paper constitutes an attempt to investigate the physiological mechanism by means of which the swim bladder performs this role. Our observations were made on Cyprinidae (Cyprinus carpio L.). The method employed was as follows. A longitudinal slit of 3-4 cm. was made on the side of the Fig. 2 Fig. 3 Fig. 2. 1, movements of tail; 2, movements of fin; 3, respiratory movements; 4, time (in 10-sec. periods). Lower tracing indicates moment of increase of pressure in swimming bladder to 80 mm. Hg. Strong movements of fins and downward movements of tail. Respiratory movements, after an increase, return to the normal. Fig. 3. 1, movement* of tail; 2, movements of fin; 3, respiratory movements; 4, heart contractions; S, time (in io-«ec. periods). Lower tracing indicates moment of elevation of pressure to 80 mm. Hg. Strong movements of tail and especially fins. fish, opposite the abdominal fin, at the level of the swim bladder. The anal extremity of the swim bladder was carefully pulled out and afineglass cannula was introduced into the opening; in a later stage of the experiment this cannula was joined to a manometer by means of an india-rubber tube. The n. vago-sympathicus was carefully exposed along the course of the air duct of the swim bladder and placed on JKB'XIVi a;

i8 CH. S. KOSHTOJANZ and PH. D. VASSILENKO isolated electrodes. The operation was performed with the greatest caution so as not to injure the internal organs of the fish.

7 i8 CH. S. KOSHTOJANZ and PH. D. VASSILENKO isolated electrodes. The operation was performed with the greatest caution so as not to injure the internal organs of the fish. The sides of the wound were carefully sewn together. The fish thus prepared was placed belly upwards, and fresh water was made to pass through its mouth. The movement of the fins, the gills, and the heart were registered by means of small levers of a recording drum. Fig. i presents the details of the experiment. Fig. 4 Fig. 5 Fig. 4. Designations as in Fig. 3. Lower tracing shows moment of stimulation of n. vago-sympathicus with induction current. Strong movements of all fin* and marked slowing of heart rhythm. Fig. 5. Designations as in Fig. 3. Lower tracing shows moment of elevation of pressure to 100 mm. Hg. No effect after cutting the N. n. vago-sympathici. There can be no doubt as to the participation of the swim bladder in the coordination of movements. During an experiment we could augment or decrease the pressure within the swim bladder and observe the reaction of the other organs. An increase of pressure in the swim bladder up to mm. of water caused strong movements of all the fins (Fig. 2), and a reaction from the respiratory muscles and the heart. In addition to the movements of the fins, the increase of pressure in the swim bladder produces, first stimulation', and then a depression of respiration and of the cardiac contractions (Figs. 2-3). In relation to this, it should be noted

On the Receptor Function of the Swim Bladder of Fishes 19 tnat it was found by v. Saalfeld (1933) that the cardiac rhythm is altered when there is a dilatation of the lungs.

8 On the Receptor Function of the Swim Bladder of Fishes 19 tnat it was found by v. Saalfeld (1933) that the cardiac rhythm is altered when there is a dilatation of the lungs. The movements of the fins are not disorderly, but unidirectional, as can be also seen in Figs. 2 and 3. Under natural conditions, when the pressure of the water upon the fish increases, the tail fin makes a downward movement, permitting the fish to swim upwards, while the thoracic fin makes rotatory movements, enabling the fish to rise head upward. Such was also the position of the fins in our experiments; it persisted for a long time after the stimulation of the swim bladder had ceased. When the pressure in the bladder increases, walls of the bladder become distended, and the numerous nerve endings in them (Deineka, 1905) are stimulated. The impulses reach the central nervous system by means of the vagus. Moreover, a reflex response from the swim bladder can be obtained not only by increasing the pressure, but also by lowering it. High pressure is not stationary once it is reached, but falls to the normal in the course of a few seconds, as the air goes out of the swim bladder through the ductus pneumaticus. It was easy to prove that it is along the n. vago-sympathicus that the impulses are transmitted. In the above experiment we demonstrated that the electric stimulation of the n. vago-sympathicus produces the same effect (Fig. 4) as does an increase of pressure in the swim bladder. Fig. 4 shows the movements of the fins, the increased breathing movements and the slowing down of the cardiac rhythm brought about by the stimulation of the nerve. After section of the n. vago-sympathicus, increased pressure in the bladder does not lead to any movement of the fins, nor to any reaction of respiratory muscles or heart (Fig. 5). These facts show in a convincing manner that the swim bladder is a receptor organ and that its stimulation can evoke reflexes in the skeletal musculature as well as in other organs by means of impulses transmitted by the n. vago-sympathicus. On the basis of these data, obtained in acute experiments, we have now begun a series of systematic observations upon operated fishes under aquarium conditions, which ought to elucidate the biological significance of the phenomena described. CONCLUSIONS 1. A rise in pressure of the gas in the swim bladder of Cyprinus carpio produces strong responses of all fins and a reaction of the respiratory organs (first an activation, then a depression) and of the heart (depression of the cardiac rhythm). The same effects are obtained by stimulating the branch of the n. vago-sympathicus leading to the bladder. 2. After the section of this branch of n. vago-sympathici, a change of pressure in the bladder produces no effect on the fins, the respiratory and cardiac muscles. REFERENCES DEINEKA, D. (1905). Z. wist. Zool. 78, 149. VON SAALFELD, E. (1933). PflUg. Arch. ges. Physiol. 231, 33.

transients' of large amplitude can be imposed on the arterial, cardiac and Since both coughing and the Valsalva manoeuvre raise intrathoracic pressure

transients' of large amplitude can be imposed on the arterial, cardiac and Since both coughing and the Valsalva manoeuvre raise intrathoracic pressure 351 J. Physiol. (I953) I22, 35I-357 EFFECTS OF COUGHING ON INTRATHORACIC PRESSURE, ARTERIAL PRESSURE AND PERIPHERAL BLOOD FLOW BY E. P. SHARPEY-SCHAFER From the Department of Medicine, St Thomas's Hospital