QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by MOHRI, H. Articles by YASUMASU, I. Search for Related Content PubMed PubMed Citation Articles by MOHRI, H. Articles by YASUMASU, I.

Journal of Experimental Biology 40,573-586 (1963)
Published by Company of Biologists 1963

Studies on the Respiration of Sea-Urchin Spermatozoa : V. The Effect of P_CO2

H. MOHRI ¹ and I. YASUMASU ²

¹ Stazione Zoologica Naples, Italy
² Biological Institute, College of General Education, University of Tokyo, Komaba, Meguroku, Tokyo, Japan

1. The effect of P_COCO2 on the respiration and motility of sea-urchin spermatozoa was studied on Anthocidaris crassispina. Some points were also corroborated on Hemicentrotus pulcherrimus, Pseudocentrotus depressus, Paracentrotus lividus and Sphaerechinus granularis.

2. It was found that any level of CO₂ above 1%, both in oxygen and in air, inhibited the O₂ uptake of spermatozoa suspended in sea water, measured polarographically with a vibrating platinum electrode. The inhibitory effect paralleled the P_COCO2 and was completely reversed by introducing oxygen or air.

3. pH variations between 8.50 and 6.75 had no influence on O₂ uptake, when the pH was stabilized with 0.05 Mhistidine-HCl-NaOH. O₂ uptake was, however, reduced to some extent outside this range, especially on the acid side. Although the increase in P_COCO2 is inevitably followed by a decrease in pH, the inhibitory effect of CO₂ far exceeds that caused by the reduction in pH.

4. The O₂ uptake rate was little affected by the addition of both bicarbonate and carbonate ions to the suspending medium, although the former had a slightly stimulating effect at certain concentrations.

5. In buffered sea water, CO₂ had little influence on O₂ uptake even at partial pressures as high as 10% which inhibited the bulk of O₂ uptake in sea water.

6. Sperm motility was also inhibited by CO₂. In this case, too, the inhibition paralleled the P_COMCOM2 and was completely reversible. The effect was more pronounced in air than in oxygen, and in dense sperm suspensions than in dilute ones.

7. These results suggest that gaseous CO₂ is the factor responsible for the inhibitory effect. The possible role of CO₂ in the dilution phenomena of sea-urchin spermatozoa is discussed.

Note:

On leave from the Biological Institute, College of General Education, University of Tokyo, Tokyo, Japan, as recipient of a scholarship from the Italian Government (1962-63). The travelling expenses were granted by the Japanese Government.

This article has been cited by other articles:

				M Morisawa and K Suzuki Osmolality and potassium ion: their roles in initiation of sperm motility in teleosts Science, December 5, 1980; 210(4474): 1145 - 1147. [Abstract] [PDF]