Link Between Nicotine Addiction And Autism (part 2)
"Now that these associations have been made, we believe that nicotine in smokers' brains possibly increases the level of neurexin-1 and, as a consequence, helps bring more receptors to the synapses and makes those circuits highly efficient, reinforcing the addiction. In autism, we have the opposite problem. We have a lack of these receptors, and we speculate that neurexin levels are lower," he said.
"Our research reveals how changes in the functions of neurexin could affect the guidance of nicotinic acetylcholine receptors to their functional destinations in nerve cells, perhaps increasing receptors in tobacco addicts while decreasing them in autistic individuals, thus increasing susceptibility to these devastating neurological disorders."
Autism symptoms include impaired social interaction, problems with verbal and nonverbal communication, and repetitive or severely limited activities and interests. An estimated three to six of every 1,000 children are diagnosed with autism, and boys are four times more likely than girls to have the disorder, according to the National Institute of Neurological Disorders and Stroke.
Anand and colleagues were studying drug abuse and addiction when they discovered the neurexin-1 beta protein's relationship to a certain type of nicotinic receptor. The timing of the discovery was key, as it built upon two other research groups' previous observations: The brains of people with autism and other neurological disorders that were examined after their death showed a 60-percent to 70-percent decrease in specific nicotinic receptors, and some patients with autism have mutations in the neurexin-1 gene that suggest the gene's improper functions could play a role in the disorder.
"These have all been 'association studies.' None has been able to prove what causes autism," Anand said. "And then we accidentally discovered that neurexin-1 and nicotinic receptors tangle. So we knew that there was a genetic link to the process leading to synapse formation, and we had nicotinic receptors that had disappeared in the brains of autistic patients. Our finding filled a gap by saying there is a physical and functional association between these two things occurring in the brain."
Neurexin has implications for tobacco addicts, as well, Anand said. Yet another group of researchers recently found that people with a mutation in the neurexin-1 gene were more likely to be smokers, meaning changes in the gene's functions that lead to excess levels of the nicotinic receptors might make people more susceptible to nicotine addiction.
"Our research reveals how changes in the functions of neurexin could affect the guidance of nicotinic acetylcholine receptors to their functional destinations in nerve cells, perhaps increasing receptors in tobacco addicts while decreasing them in autistic individuals, thus increasing susceptibility to these devastating neurological disorders," Anand said.
The finding also has implications for nicotine addiction because drugs known to alter neurexin's guidance of nicotinic receptors within nerve cells could be used to suppress tobacco addiction.
"Our research reveals how changes in the functions of neurexin could affect the guidance of nicotinic acetylcholine receptors to their functional destinations in nerve cells, perhaps increasing receptors in tobacco addicts while decreasing them in autistic individuals, thus increasing susceptibility to these devastating neurological disorders."
Autism symptoms include impaired social interaction, problems with verbal and nonverbal communication, and repetitive or severely limited activities and interests. An estimated three to six of every 1,000 children are diagnosed with autism, and boys are four times more likely than girls to have the disorder, according to the National Institute of Neurological Disorders and Stroke.
Anand and colleagues were studying drug abuse and addiction when they discovered the neurexin-1 beta protein's relationship to a certain type of nicotinic receptor. The timing of the discovery was key, as it built upon two other research groups' previous observations: The brains of people with autism and other neurological disorders that were examined after their death showed a 60-percent to 70-percent decrease in specific nicotinic receptors, and some patients with autism have mutations in the neurexin-1 gene that suggest the gene's improper functions could play a role in the disorder.
"These have all been 'association studies.' None has been able to prove what causes autism," Anand said. "And then we accidentally discovered that neurexin-1 and nicotinic receptors tangle. So we knew that there was a genetic link to the process leading to synapse formation, and we had nicotinic receptors that had disappeared in the brains of autistic patients. Our finding filled a gap by saying there is a physical and functional association between these two things occurring in the brain."
Neurexin has implications for tobacco addicts, as well, Anand said. Yet another group of researchers recently found that people with a mutation in the neurexin-1 gene were more likely to be smokers, meaning changes in the gene's functions that lead to excess levels of the nicotinic receptors might make people more susceptible to nicotine addiction.
"Our research reveals how changes in the functions of neurexin could affect the guidance of nicotinic acetylcholine receptors to their functional destinations in nerve cells, perhaps increasing receptors in tobacco addicts while decreasing them in autistic individuals, thus increasing susceptibility to these devastating neurological disorders," Anand said.
The finding also has implications for nicotine addiction because drugs known to alter neurexin's guidance of nicotinic receptors within nerve cells could be used to suppress tobacco addiction.
posted by Natural Health Sites at
10:29 PM
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