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Haemoglobin function in intact Lampetra fluviatilis erythrocytes
1Department of Zoology, University of Helsinki, Finland.
Respiration Physiology
|March 1, 1993
Summary
Lamprey red blood cells maintain a high pH, crucial for efficient oxygen binding and transport. This high pH optimizes hemoglobin-oxygen affinity, ensuring effective oxygen uptake in the gills.
Area of Science:
- Physiology
- Biochemistry
- Comparative Animal Physiology
Background:
- The Bohr effect describes the influence of pH on hemoglobin-oxygen affinity.
- Understanding red blood cell pH regulation is vital for comprehending oxygen transport in aquatic vertebrates.
- Lampetra fluviatilis (sea lamprey) exhibits unique physiological adaptations.
Purpose of the Study:
- To investigate the relationship between red blood cell pH and oxygen saturation in Lampetra fluviatilis.
- To determine the impact of red blood cell pH on hemoglobin-oxygen affinity.
- To elucidate the physiological significance of high red cell pH in lampreys.
Main Methods:
- Measurements of red cell pH across a range of intracellular pH values (6.7-8.0).
- Analysis of hemoglobin-oxygen binding curves at varying pH levels.
- Determination of the Bohr factor and P50 values.
Main Results:
- A maximal increase in red cell pH of 0.326 units upon deoxygenation was observed at an oxygen-saturated erythrocyte pH of 7.7.
- Hemoglobin-oxygen affinity was highly pH-dependent, with a Bohr factor of -1.03.
- At physiological pH (7.67), the P50 value was 28.2 Torr, significantly lower than at a pH of 7.33 (73 Torr).
Conclusions:
- The high red cell pH in lampreys is essential for effective oxygen loading in the gills.
- Elevated red cell pH maximizes the apparent cooperativity of oxygen binding in Lampetra fluviatilis.
- These findings highlight a critical adaptation for oxygen transport in this species.