Intracranial self-administration of morphine into the ventral tegmental area in rats

MA Bozarth, RA Wise - Life sciences, 1981 - Elsevier
Life sciences, 1981Elsevier
The rewarding properties of morphine injected directly into the ventral tegmental area were
investigated using a self-administration procedure. Experimentally naive rats demonstrated
rapid acquisition of a lever-pressing response which produced a 100 ng infusion of
morphine sulfate solution. Response rates were relatively stable and markedly exceeded
lever-press rates of rats passively receiving the same pattern of infusions (ie, yoked control
procedure). Intracranial self-administration was effectively blocked by naloxone suggesting …
Abstract
The rewarding properties of morphine injected directly into the ventral tegmental area were investigated using a self-administration procedure. Experimentally naive rats demonstrated rapid acquisition of a lever-pressing response which produced a 100 ng infusion of morphine sulfate solution. Response rates were relatively stable and markedly exceeded lever-press rates of rats passively receiving the same pattern of infusions (i.e., yoked control procedure). Intracranial self-administration was effectively blocked by naloxone suggesting that this behavior is mediated through opiate receptors and is not the consequence of mechanical trauma, or changes in osmolarity or pH.
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