Cold or warm adaptation usually results in changes of the cellular parameters of poikilothermic animals. However, no data are available about the changes in cellular parameters of sperm samples from cold or warm adapted animals. Here the effects of warm and cold adaptation on the spermation of common carp (Cyprinus carpio L.) and the changes in the characteristics of the individual sperm cells are described. Measurements were carried out on semen samples from 10 warm adapted and 10 cold adapted animals. The sperm cells from the cold adapted animals had a higher intracellular pH (7.4 ± 0.1) than those from the warm adapted ones (7.1 ± 0.1). The pH of the seminal plasma of the cold adapted animals (8.6 ± 0.2) was also higher than that of the warm adapted animals (8.3 ± 0.1). The concentration of spermatozoa in the semen of cold adapted animals was about half that for the warm adapted animals (0.7 ± 0.1 x 1010 vs. 1.4 ± 0.2 x 1010 cells/ml). The Na+ concentration of the seminal plasma of the cold adapted animals (83 ± 12 mM) was higher, while the K+ concentration in these samples (64 ± 11 mM) was lower than the corresponding data for the warm adapted animals (63 ± 10 mM and 87 ± 16 mM, respectively). All of these differences proved to be significant at 5% level of significance using the Student's t-test. In contrast, there was no significant difference between the intracellular free K+ concentrations in the spermatozoa from cold and warm adapted animals (58 ± 8 mM vs. 60 ± 7 mM). The ion compositions and concentrations of the blood sera of cold and warm adapted animals were similar. Also, the motile fraction and duration of motility of the spermatozoa from cold and warm adapted animals were identical. An increase by 0.2 pH unit occurred in the intracellular pH during hypoosmotic shock induced motility of sperm cells from the cold and warm adapted animals. This pH increase could be blocked by the Na+/H+ exchange inhibitor amiloride in a concentration of 100 μM. Based on the kinetics of the processes involved and on additional experimental evidence it is suggested that the hypoosmotic shock induced immediate hyperpolarization of the sperm under usual spawning conditions. Thus, it may be a regulatory step in the motility activation of common carp sperm but not in the relatively slowly occurring intracellular alkalinization.
ASJC Scopus subject areas
- Aquatic Science