Hsiao S, Smith G P
Department of Psychology, University of Arizona, Tucson 85721.
Pharmacol Biochem Behav. 1995 Jan;50(1):121-5. doi: 10.1016/0091-3057(95)00315-n.
Dopaminergic D1 and D2 antagonists decrease the intake of sweet solutions during sham feeding. Because the decreased intake of 10% sucrose produced by the D1 and D2 antagonists has been demonstrated to occur in the absence of significant deficits in the initiation of ingestion, or of its motor performance, we investigated the hypothesis that raclopride decreases intake by lowering the reinforcing potency of the orosensory stimulation provided by sucrose during sham feeding. Rats were adapted to ingest two differently flavored 10% sucrose solutions for 5 min in one-bottle tests. The flavored solution that rats preferred was paired with pretreatment with a dose of raclopride (400 micrograms/kg, IP, 15 min) that produced a mean decrease of intake of 55%. The other flavored 10% sucrose solution was paired with vehicle (0.15 M NaCl) injections. After three or six pairings with raclopride or vehicle injection, two two-bottle preference tests were given without raclopride pretreatment. Preference for the flavored 10% sucrose solution previously paired with raclopride decreased significantly in both tests. We interpret this decreased preference as evidence that raclopride decreased the reinforcing potency of flavored 10% sucrose during one-bottle tests. This is consistent with our hypothesis and with the more general hypothesis of Wise that central dopaminergic mechanisms mediate the reinforcing effect of food.
多巴胺能D1和D2拮抗剂在假饲期间会减少甜味溶液的摄入量。由于已证明D1和D2拮抗剂导致的10%蔗糖摄入量减少，是在摄食起始或其运动表现没有明显缺陷的情况下发生的，因此我们研究了如下假设：雷氯必利通过降低假饲期间蔗糖提供的口部感觉刺激的强化效力来减少摄入量。在单瓶试验中，让大鼠适应于摄入两种不同口味的10%蔗糖溶液5分钟。将大鼠偏好的口味溶液与一剂雷氯必利（400微克/千克，腹腔注射，15分钟）预处理配对，该剂量使摄入量平均减少55%。另一种口味的10%蔗糖溶液与溶剂（0.15 M氯化钠）注射配对。在与雷氯必利或溶剂注射进行三次或六次配对后，在不进行雷氯必利预处理的情况下进行了两次双瓶偏好试验。在这两次试验中，对先前与雷氯必利配对的口味10%蔗糖溶液的偏好均显著降低。我们将这种偏好降低解释为雷氯必利在单瓶试验期间降低了口味10%蔗糖的强化效力的证据。这与我们的假设以及怀斯提出的更普遍的假设一致，即中枢多巴胺能机制介导食物的强化作用。
