Δ9-Tetrahydrocannabinol (Δ9-THC) attenuates mouse sperm motility and male fecundity.
Numerous studies have shown that N-arachidonoylethanolamine (AEA) can inhibit sperm motility and function but the ability of cannabinoids to inhibit sperm motility is not well understood. We investigated the effects of WIN 55,212-2, a CB(1) cannabinoid receptor agonist, and Δ(9) -tetrahydracannabinol (Δ(9) -THC) on the ATP levels and motility of murine sperm in vitro. In addition, the effects of acute administration of Δ(9) -THC on male fecundity were determined. Effects of Δ(9) -THC on basal sperm kinematics were determined using computer-assisted sperm analysis (CASA). Stop-motion imaging was performed to measure sperm beat frequency. The effect of Δ(9) -THC on sperm ATP was determined using a luciferase assay. Male fertility was determined by evaluating the size of litters sired by Δ(9) -THC-treated males. KEY RESULTS Pretreatment of sperm for 15 min with 1 µM Δ(9) -THC reduced their basal motility and attenuated the ability of bicarbonate to stimulate flagellar beat frequency. Treatment with 5 µM WIN 55,212-2 or 10 µM Δ(9) -THC for 30 min reduced sperm ATP levels. In sperm lacking CB(1) receptors this inhibitory effect of WIN 55,212-2 on ATP was attenuated whereas that of Δ(9) -THC persisted. Administration of 50 mg·kg(-1) Δ(9) -THC to male mice just before mating caused a 20% decrease in embryonic litter size. Δ(9) -THC inhibits both basal and bicarbonate-stimulated sperm motility in vitro and reduces male fertility in vivo. High concentrations of WIN 55,212-2 or Δ(9) -THC inhibit ATP production in sperm this effect of WIN 55,212-2 is CB(1) receptor-dependent whereas that of Δ(9) -THC is not. LINKED ARTICLES This article is part of a themed section on Cannabinoids in Biology and Medicine. To view the other articles in this section visit httpdx.doi.org10.1111bph.2012.165.issue-8. To view Part I of Cannabinoids in Biology and Medicine visit httpdx.doi.org10.1111bph.2011.163.issue-7.