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Specimens of rainbow trout (Salmo gairdneri) were electrically stimulated to exhausting activity in a closed water recirculation system and the changes in dorsal aortic plasma pH, PCO2, PO2, O2 content, [Na+], [Cl-], [K+], [Lactate-] and Ht were measured during a 24 h recovery period. Net transfer of H+, Na+, Cl- and ammonia between fish and environment(More)
Exposure of the elasmobranch Scyliorhinus stellaris to environmental hyperoxia (PO2 of 500 mm Hg) resulted in a considerable rise of arterial PCO2 from 1.9 mm Hg during normoxia to about 11 mm Hg after 6 days as an expression of the primarily oxygen-oriented regulation of gill ventilation. In contrast to the typical pattern during environmental hypercapnia,(More)
The influence of hypoxia upon the heart rate and the rate and amplitude of breathing in the tench has been reported by Randall & Shelton (1963). Satchell (1961) demonstrated that dogfish respond to anoxia by decreasing heart rate, temporarily increasing dorsal aortic blood pressure and increasing the mean and pulse pressure in the ventral aorta. These fish(More)
Rainbow trout (Salmo gairdneri) were electrically stimulated to exhausting activity and the changes in cardiac output and blood flow distribution to gills and systemic tissues resulting from the developing severe lactacidosis were repeatedly measured by the microsphere method (15 ̂ m). Determination of cardiac output by application of the Fick principle(More)
The purpose of this investigation was to explore the ontogeny of certain respiratory responses of rainbow trout. Adult trout respond to hypoxia with an increase in the flow of water over the respiratory surfaces, and with a reflex bradycardia (Holeton & Randall, 1967). When adult rainbow trout are exposed to 5% carbon monoxide (CO) and thus rendered(More)
Specimens of Conger conger (L.) were exposed to environmental hypercapnia in a closed recirculating seawater system. Arterial plasma pH, PCO2 and bicarbonate concentration, as well as the net transfer of bicarbonate and ammonia between fish and ambient seawater, were monitored for 30 h of hypercapnia. The initial hypercapnia-induced reduction of arterial pH(More)
Specimens of the larger spotted dogfish (Scyliorhinus stellaris) were electrically stimulated to exhaustion in a closed seawater recirculation system. The production of large quantities of lactic acid by anaerobic metabolism and the resultant efflux of the dissociation products, H+ and lactate, from the white musculature resulted in severe acid-base(More)
Hughes & Shelton (1962), Hughes (1964) and Rahn (1966) have analysed gas exchange in animals in an aquatic environment, particularly fish, from a theoretical viewpoint. These authors provide equations which permit a quantitative analysis of the gas-exchange process. From these, it is possible to determine the relative effectiveness of the exchange process(More)