But it turns out, I actually have quite a little pile of these cannabis and sperm papers, so maybe I'll do a little series! Get ready for your little swimmers to get hiiiiiiigh.
Morgan et al. "D9-Tetrahydrocannabinol (D9-THC) attenuates mouse sperm motility and male fecundity" British Journal of Pharmacology, 2012.
We often think about how cannabis, and its most famous ingredient, D9-THC (delta9-tetrahydrocannabinol) might impact our brains and behavior. But it's time for us to pause, and think about what's really important: our junk.
Yes, behavior and short term memory are one thing, but your SPERM! The very future of the species may hang in the balance of our pot-imbued balls.
But seriously, it is actually important to determine how D9-THC might be affecting fertility. Cannabis is very widely used, which makes it important to know all the possible effects. And if it can affect your sperm...well sperm, under the right conditions, meet eggs and turn into zygotes, which, with proper conditioning, turn into more people. While the long term effects of cannabinoids on subsequent offspring haven't been determined, figuring out how cannabis affects sperm itself is a good place to start.
And there's very good reason to look at sperm. D9-THC acts on the cannabinoid-1 receptor (CB1), and the cannabinoid-2 receptor (CB2). CB1 is present in mouse sperm, and human sperm has both CB1 and CB2. It's clear that sperm are meant to be sensitive to cannabinoids that are naturally present in the body (we call them the endocannabinoids).
But just what does D9-THC do to sperm? The authors of this study decided to look at sperm motility and energy (in the form of ATP). The took a bunch of mouse sperm, put it in a dish, and applied some D9-THC in a low concentration.
You can see above the measures of sperm motility. You can also see that D9-THC decreased the motility and the beating frequency of the sperm tail, which ended up producing decreased sperm velocity. Slooooooooooow sperm.
And that's all well and good. Don't put pot on your sperm in a dish. But what does that say about in vivo? To find this out, the authors gave a single injection of D9-THC (50 mg/kg, no word on how relevant this is to human dosing, though) to male mice, and let them get it on with some ladies. After mating, they kept track of the females, and looked at litter size (the number of pups), to see if the D9-THC had impacted fertility.
And so it did.
You can see on the left the normal mice and their litter sizes with vehicle or following D9-THC. D9-THC reduced the litter size by 20%, a pretty substantial reduction (say a normal little is 10 pups, well now it's 8). But you can also see that this effect depends on the presence of the CB1 receptors, CB1 knockout mice had no effects on litter size.
So it looks like, while the WiFi may not be coming for your sperm, with weed you may not be so lucky! But it still remains to be seen what will happen in humans, and if it affects human fertility like it does it mice.
...and luckily for you all, I've got a paper on that! Come back next week!
Morgan, D., Muller, C., Murataeva, N., Davis, B., & Mackie, K. (2012). Δ9-Tetrahydrocannabinol (Δ9-THC) attenuates mouse sperm motility and male fecundity British Journal of Pharmacology, 165 (8), 2575-2583 DOI: 10.1111/j.1476-5381.2011.01506.x