1 research outputs found
MinogianisDataFiles.xlsx
<p><a>The faster drugs of abuse reach the brain,
the greater is the risk of addiction. Even small differences in the rate of
drug delivery can influence outcome. Infusing cocaine intravenously over 5
versus 90-100 seconds promotes sensitization to the psychomotor and incentive
motivational effects of the drug and preferentially recruits mesocorticolimbic
regions. It remains unclear whether these effects are due to differences in how
fast and/or how much drug reaches the brain.</a> <a>Here, we predicted that varying the rate of intravenous cocaine
infusion between 5-90 seconds produces different rates of rise of brain drug concentrations,
while producing similar peak concentrations. Freely-moving male Wistar rats received
acute intravenous cocaine infusions (2.0 mg/kg/infusion) over 5, 45 and 90 seconds.
</a><a>We measured cocaine concentrations in the dorsal
striatum using rapid-sampling microdialysis (1 sample/minute) and high-performance
liquid chromatography-tandem mass spectrometry. We also measured extracellular concentrations
of dopamine and other neurochemicals. Regardless of infusion rate, acute
cocaine did not change concentrations of non-dopaminergic neurochemicals. Infusion
rate did not significantly influence peak concentrations of cocaine or dopamine,
but concentrations increased faster following 5-second infusions. </a><a>We also assessed psychomotor activity as a function of
cocaine infusion rate. Infusion rate did not significantly influence total locomotion,
but locomotion increased earlier following 5-second infusions. Thus, small
differences in the rate of cocaine delivery influence both the rate of rise of
drug and dopamine concentrations and psychomotor activity. A faster rate of rise
of drug and dopamine concentrations might be an important issue in making
rapidly delivered cocaine more addictive.</a></p