Nature Paper
By Francesco Pontieri et al. , Nature 382, 18 July, 1996, page 255-257.
The paper assigned to us by Dr. Dodson described how nicotine produced similar responses in rats as other addictive drugs, such as cocaine and morphine.
Introduction
Nicotine is tested for its effects on the nucleus accumbens region of the brain,
an area thought to be involved in emotional responses. Specifically, they were
searching for dopamine transmission in that area and for glucose metabolism levels
on and after the administration of nicotene.
Experimental Methods
Rats were subjected to intravenous doses of nicotene, 0.025 mg/kg and 0.050 mg/kg.
They were then killed (by sodium pentobarbital) and their brains were autoradiographed
to determine glucose utilization levels. For the measurements of dopamine transmission,
rats were immobilized, a small hole was drilled in the skull and a dialysis probe was
inserted into each hemisphere of the brain, one aimed at the core and one at the shell
of the nucleus accumbens region.
Results/Conclusions
Results of this experiment point towards an increase in dopamine transmission in the
nucleus accumbens area of the brain and an increase in glucose metabolism upon
administration of nicotine. However, sample sizes were very small (n=4), and only one
data point given (glucose use at 0.050 mg/kg dose of nicotine) was marked as a "significant
variation(s) with respect to values measured in the control group."
The authors take this as evidence that nicotine shares the dopamine increasing ability with addictive drugs.
Implications/Applications
Although this experiment had low sample sizes and only one data point of merit, if it were
repeated with more convincing results, it may stand to reason that nicotine could be considered
an addictive drug, alongside cocaine and heroin.
This, in turn, could influence public policy towards tobacco use.
