ISSN:
1432-136X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary 1. Chronically hypoxic crayfishAstacus leptodactylus at 20°C were transiently exposed (1 or 2 minute tests) to either hyperoxic, hypercapnic, normoxic, or normoxic and hypercapnic waters. Using O2 probes to monitor changes in O2 levels of the inspired water and of the hemolymph in the pericardial sinus following brief O2 exposures, the ventilatory response delay and circulation time required for hemolymph to reach the heart and hence the central nervous system (CNS) were followed. In some CO2 tests, fast pH probes recorded changes of hemolymph pH in the pericardial cavity. 2. All crayfish exhibited a CO2 induced hyperventilation. At $$PI_{O_2 } $$ = 40–50 Torr, the ventilatory response to CO2 tests started before the O2 labelled hemolymph could have reached the CNS. The CO2 response delay was shortened when the rate of ventilation was increased by lowering $$PI_{O_2 } $$ from 70 to 40 Torr. As circulation time is not shortened in these conditions (Massabuau and Burtin 1984), it is concluded that CO2 chemoreceptors are present in the branchial cavities. The importance of a central CO2 chemosensitivity is discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00692933
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