Researchers found that chloride levels are higher in the neurons of "autistic" mice, and remain at abnormal levels from birth.
The study suggests diuretics administered before birth could help prevent these abnormalities, a, INSERM (Institut national de la santé et de la recherche médicale) news release reported. It also suggests the birth hormone oxytocin could help reduce chloride levels.
Neurons normally contain high levels of chloride throughout the embryonic stage; this causes GABA ("the main chemical messenger of the brain") to "excite" neurons instead of inhibiting them.
A reduction in chloride levels promotes GABA's inhibiting properties allowing it to regulate the brain from on. Brain disorders such as childhood epilepsy and cranial trauma have been linked to higher chloride levels.
"The researchers showed that administration of a diuretic to children with autism (which reduces neuronal chloride levels) has beneficial effects. The results of the trial supported this hypothesis, but because high neuronal chloride levels could not be demonstrated in children with autism, it was not possible to prove the mechanism proposed or justify the treatment," the news release reported.
The team looked at the chloride levels in rodent neurons both before and after birth. They found neuronal chloride levels are elevated in both young and adult mice included in an autism model. The team saw "aberrant electrical activities in the brain" linked to GABA.
"Chloride levels during delivery are determinants of the occurrence of autism spectrum disorder," Yehezkel Ben-Ari, an Emeritus Research Director at Inserm said in the news release.
The team adminisdtered a diuretic treatment to the mother for about 24 hours before delivery; they noticed a drop in chloride levels that lasted for weeks after the initial treatment. They believe this treatment corrected "autistic" traits in adulthood.
The team tested the effectiveness of oxytocin treatment as well by injecting pregnant mice with a drug that blocks oxytocin signals. They found this "reproduced the entire autism-like syndrome."
"These data validate our treatment strategy, and suggest that oxytocin, by acting on the chloride levels during delivery modulates/controls the expression of autism spectrum disorder," Yehezkel Ben-Ari said.
The finding suggests when taken together these two treatments could help prevent autism.
