Pot Smoking to 3rd generation feels effects

"Metabolic and behavioral effects of cannabis in rats during adolescence were passed down to multiple generations of male offspring, even though these animals were not themselves exposed to the drug, a researcher said here.

Male rats born to parents who had received injections of tetrahydrocannabinol (THC) when young -- but reared by drug-naive surrogate rat mothers -- weighed more than otherwise similar rats whose parents received saline injections, yet showed less motivation to seek highly tasty foods, said Yasmin Hurd, PhD, of Mount Sinai School of Medicine in New York City.
Preliminary results from a follow-up study indicated that third-generation male offspring did not put on extra weight through their first 2 months of life, but did show differences in motivation to seek highly tasty food, as was seen in the second-generation rats. 

Hurd told attendees at the Society for Neuroscience's annual meeting.
Epigenetic analyses revealed numerous alterations induced by THC exposure in the founder rats (F0 generation), which might have passed down to offspring,....

Hurd and colleagues were exploring the mechanisms that 

account for apparently permanent effects of temporary cannabis exposure seen in animals, which persist long after the exposure stops. 

Earlier studies in her lab had shown, for example, that dosing rats with THC during adolescence increased their interest in heroin self-administration during their adulthood.
F1 males in the THC group did show "an unusual avoidance behavior" when a bright light was flashed in their spaces.
Another effect of the F0 THC exposure on male offspring was to increase long-term depression in the dorsal (but not ventral) striatum following electrical stimulation. 

This region is involved with habit formation and obsessive behaviors, Hurd said." 

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