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Intravenous Self-Administration
This procedure is used to assess the reinforcing properties of
drugs. Animals under no motivational constraints are allowed to
intravenously (IV) self-administer all drug classes known to
have abuse potential in limited daily 2 hour sessions. In some
cases, the rats will be allowed to self-administer drugs for an
extended period of time, and in cases where the animals have
continuous access to self-administration, the rats will also
have access to food and water. In all experimental procedures,
the animal has the option not to respond and operationally finds
the drugs reinforcing since the animal itself self-administers
the drug. This is the most direct means of assessing the
motivational properties of drugs and provides a model of
drug-seeking behavior in humans.
Conditioned Place Preference/Aversion
Place conditioning testing is frequently used to study the
effects of drugs that produce both rewarding effects and
aversive effects. Current theories of addiction benefit from our
understanding that specific regions in the brain are involved in
the reinforcing/rewarding properties of drugs that possess high
liability for abuse. The reinforcing efficacy of many classes of
drugs are mediated by interactions with their receptors in the
mesocorticolimbic system, and abuse liability of such compounds
is sometimes measured using place conditioning. In place
conditioning studies, subjects are treated by pairing
distinctive environmental cues with an unconditioned stimulus (UCS).
The UCS may be a drug. The subjects are later given the
opportunity to spend time in the presence of cues associated or
not associated with the UCS. In place aversion testing, the
decrease in time that the subject spends in the environment
paired with the UCS, at this later time, in relation to the time
spent before UCS pairing, is an index of the aversive properties
of the UCS. In place preference testing, the index is the
increased time spent in the environment paired with the UCS, at
this later time, in relation to the time spent before UCS
pairing.
Custom Abuse Liability Models
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