CANNABIS CAN HALT 'FERTILITY SIGNALS'

Cannabis smokers may be lowering their chances of having children,
according to research. Scientists have discovered that chemicals in the
drug can overload an important signalling system in the brain which is
involved in fertility. When consumed by men or women, marijuana can make
sperm sluggish, reduce the chances of it breaking through the surface of an
egg and hinder the development of a newly-fertilised embryo.

Dr Herbert Schuel, from the University at Buffalo, New York State, who
presented the findings at the annual meeting of the American Society for
Cell Biology, said: "These findings suggest that defects in the cannabinoid
receptor-signalling system could account for certain types of infertility.

"A better understanding of these mechanisms might lead to the development
of novel drugs useful in reproductive medicine. For heavy marijuana users,
the study results raise the possibility that they are jeopardizing
fertility by overloading this signalling system."

In the 1980s, scientists found a chemical signalling system in the brain
that responded to THC, the active substance in marijuana. A couple of years
ago they identified the natural brain molecule anandamide that activates
these cannabinoid receptors.

Dr Schuel's team has now found the first evidence that anandamide exists in
three substances involved in fertility: human seminal plasma, mid-cycle
oviductal fluid and follicular fluid.

Human sperm is not immediately capable of fertilising sperm after
ejaculation. Only when they have been exposed to secretions inside a woman
are they able to fertilise eggs, a process called "capacitation".