Caffeine Experiment

Most people depend on that one cup of coffee to get them through the day. People are dependent on caffeine to get them going. My question is why is caffeine so addictive? Caffeine is a psychoactive drive that stimulates your body. It is in the same class as cocaine, amphetamines, and heroin though caffeine is less potent. People do not typically see caffeine as a drug of that is as addicting as other psychostimulants. These “other psychostimulants, such as amphetamines and cocaine, elevate the extracellular concentration of dopamine in the nucleus (NAc); this is believed to be one of the main mechanisms involved in the rewarding and motor-activating properties of these drugs” (Solinas 2002). In Marcello Solinas and Serge Ferré’s experiment

Caffeine and adenosine were administered to the laboratory rats. There were two methods that tested the hypothesis Motor Activity Experiment as well as in vivo microdialysis experiment. The motor activity experiment measured the motor activity of the rats after caffeine or saline (the control group) was administered into a probe that was implanted into the rats. The total horizontal motor activity was measured after caffeine or saline was put into the probes in time intervals. In the in vivo microdialysis experiment, the laboratory rates were put asleep using Equithesin to allow the experimenter to place concentric microdialysis probes in the left hemisphere of the brain. The probes were either placed in the shell of the NAc or in the core of the NAc. Twenty-four hours after the probe was implanted the experiment was performed on free moving rats. A solution that was prepare with 147 Ringer’s, 4 KCl and 2.2 CaCl, was administered into the probe at a constant rate. Samples from the rates were collected and divided. One halve was tested using electrochemical for dopamine content while the other was tested with fluorescence for glutamate content. At the end of the experiment the rats were killed to be able to preserve their brains that was used to verify the location of the implanted probe in the shell of the NAc or the core of the

The experiments also concluded “from the microdialysis experiment the preferential release of dopamine and glutamate in the shell of the NAc is also involved in the psychostimulant effects of caffeine.” (Solaris and Ferré 2002). Caffeine is region dependent in the NAc. Other psychostimulants and addictive drugs all prefentially increase extracellular levels of dopamine in the shell of NAc. This could be an explanation as to why caffeine is so addictive. The experiment that was conducted coincides with other experiments experiment results, “caffeine induces locomotor activity by acting independently of presynaptic terminals.” (Joyce and Koob 1981). This also gives reason that caffeine’s extracellular dopamine activity is region dependent. However, according to Solaris and Ferré they believe that striated regions could have an effect of how much dopamine is released they believe this because a less pronounced effect of caffeine on dopamine release was also observed in the core of the NAc which is not striated. There would need to be further experiments to be conducted to answer the question whether the striations play a role in the effects of caffeine. There would also have to be questions to answer why high dosage of caffeine did not produce any effect on extracellular dopamine