‘The percentage of teetotal monkeys matches the non-drinkers in the human population.
‘In line with human habits, most drink in moderation, 12 per cent are steady drinkers and five per cent drink to the last drop.
‘It shows that our liking for alcohol is determined largely by our genes.’
Results of the vervet monkey study by Mash et al. demonstrated that monkeys who preferred to drink the most alcohol also had a significantly higher amount of Dopamine Transporter in a brain region called the stratium when compared to their alcohol-avoidant kin—but ONLY when these former-drunk monkeys had been denied access to alcohol for some time. Sure enough, when allowed to drink, the density and distribution of Dopamine Transporter decreased as alcohol-preferring monkeys were allowed to drink; levels of DAT rebounded again during alcohol withdrawal
Similar alterations in Dopamine Transporter have been observed in human alcoholism, and interestingly, Major Depressive Disorder is also associated with higher availability of Dopamine Transporter. Perhaps this individual difference in the brain dopamine’s system can help explain why many individuals who suffer from depression appear to self-medicate with alcohol, and provide a biological target for pharmacological and cognitive therapy in these harmful disorders.
These researchers then examined the dopamine system in the brains of these animals by measuring the distribution and density of a transporter protein called the Dopamine Transporter (DAT); specifically, they compared levels of this protein in alcohol-preferring versus alcohol-abstaining monkeys.
Upon occasion, some animals drank to ataxia and unconsciousness; signs of withdrawal, including tremulousness, pacing, irritability and increased aggression, followed the abrupt discontinuation of ethanol availability. A variety of changes in social interaction, including increased orientation to external stimulus, increased incidence of stereotyped aggression and of other stereotyped behaviors and decreased frequency of affiliative behaviors were observed during ethanol periods, as compared to baseline scoring periods. In a small number of alcohol-preferring animals, CSF amine metabolites (5-hydroxyindoleacetic acid and homovanillic acid) were raised by drinking alcohol. These studies suggest that the alcohol-selecting vervet monkey may be complementary to established primate models of alcoholism.
St Kitts was chosen for the project because of reports that wild vervets had developed a liking for alcohol in the form of fermenting sugar cane in the fields of the rum-producing island. The research animals are kept in cages and given a choice of non-alcoholic, diluted alcoholic and neat drinks.
A controversial research project that involves giving alcohol to 1,000 green vervet monkeys has found that the animals divide into four main categories: binge drinker, steady drinker, social drinker and teetotaller.
The research into their drinking habits is being carried out on the Caribbean island of St Kitts. Scientists are using the monkeys - which share 96 per cent of their genetic make-up with humans - to help to search for clues to the nature of human drinking and to discover whether some people have a hereditary disposition to alcoholism - or "alcohol genes".
Researchers captured 1000 vervet monkeys from St. Kitts island, kept them in a social group and conducted research on their drinking habits. They found that the monkeys' drinking behaviours were remarkably similar to humans'
Lurking on the Caribbean island getaways of St. Kitts, Nevis and Barbados are a group of illegal aliens with a taste for alcohol. In their quest for alcohol, they've learned to steal booze from local bars and sleeping tourists.