Extracellular and Intracellular Acid–Base Status in the Freshwater Crayfish Austropotamobius Pallipes Between 1 and 12 °C
| Autor: | J. K. Naylor, N. M. Whiteley, E. W. Taylor |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
Physiology
Intracellular pH Metabolic acidosis Acid–base homeostasis Anatomy Aquatic Science Biology Crayfish biology.organism_classification medicine.disease Austropotamobius pallipes Animal science Insect Science Hemolymph Extracellular medicine Animal Science and Zoology Hepatopancreas Molecular Biology Ecology Evolution Behavior and Systematics |
| Zdroj: | Journal of Experimental Biology. 198:567-576 |
| ISSN: | 1477-9145 0022-0949 |
| DOI: | 10.1242/jeb.198.2.567 |
| Popis: | Freshwater crayfish, Austropotamobius pallipes, caught in the winter when water temperature was 5deg;C, were acclimated in the laboratory to 5deg;C for 1 week and to 1 and 12deg;C for 1 month before haemolymph and tissue samples were taken for acidshy;base analysis. In vivo, haemolymph (extracellular) pH increased by 0.14 units between 5 and 1deg;C but remained unchanged between 5 and 12deg;C, giving an overall deltapHe/deltat value of -0.009 pH unitsdeg;C-1 and an [H+] value of +3.3 nmol l-1. Haemolymph withdrawn from crayfish acclimated to 1deg;C and warmed anaerobically in vitro to 12deg;C had a deltapHe/deltat value of -0.010 pH unitsdeg;C-1. This was depressed compared with the values of -0.015 and -0.016 pH unitsdeg;C-1 obtained from haemolymph withdrawn from crayfish held at 5 and 12deg;C, respectively, but changes in H+ concentration were similar in all three groups. There was little change in intracellular pH with rise in temperature in either claw muscle (deltapHi/deltat=-0.003 pH unitsdeg;C-1) or hepatopancreas (deltapHi/deltat=-0.006 pH unitsdeg;C-1). In the heart, deltapHi/deltat paralleled that in the haemolymph (-0.010 pH unitsdeg;C-1), but the largest change was found in the abdominal muscle (-0.025 pH unitsdeg;C-1). In all tissues apart from claw muscle, there was a metabolic acidosis, with an increase in metabolic acid load as temperature rose from 1 to 12deg;C. The depressed in vivo deltapHe/deltat value and the differences in deltapHi/deltat between the tissues were attributed to active regulation of pHi, possibly to control enzyme function in the intracellular compartments. Tissues that are functionally important in the winter months, such as abdominal muscle, followed alphastat regulation, whereas tissues that are less active in the winter, such as claw muscle and hepatopancreas, maintained pHi irrespective of temperature, resulting in a relatively acidotic pHi, which may serve to depress the activity of metabolic enzymes. |
| Databáze: | OpenAIRE |
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