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EFFECTS OF ADENOSINE TRIPHOSPHATE AND CYCLIC ADENOSINE MONOPHOSPHATE ON SPERM MOTILITY IN HIGH- AND LOW-AVOIDANCE RATS (HAAS AND LAAS).
Sato, Masako1, Ohta, Ryo1, Kojima, Kohichi1, Shirota, Mariko1, 1
ABSTRACT- HAAs and LAAs were selectively inbred from Sprague-Dawley rats for high and low shuttlebox avoidance responses, respectively. In addition to these behavioral characteristics, there are obvious strain differences in sperm motion from the caudal epididymis; HAA sperm swim faster and more vigorously than LAA sperm. The aim of this study was to examine factors contributing to these differences in sperm motion. Although HAA sperm swam faster and more vigorously in incubation media for 5 min, more adenosine triphosphate (ATP) remained in HAA sperm than in LAA sperm. After 60-min incubation, however, swimming velocities of sperm and sperm ATP contents were identical in both strains. To compare sperm response to cyclic adenosine monophosphate (cAMP), HAA or LAA sperm demembranated with Triton X-100 were reactivated by 1 mM ATP and various concentrations of cAMP. Upon exposure to ATP alone, beating of the flagella was observed in both strains without strain differences in sperm motion. By coincubation with 10 or 50 
M cAMP, forward sperm was observed, and the strain differences in sperm motion of both strains were appeared. These results suggest that sperm ATP contents and response to cAMP may be candidates contributing to strain differences in sperm motion between HAAs and LAAs.
KEY WORDS: sperm motility, ATP, cAMP, shuttle-box avoidance response