Larson A A, Kondzielski M H
Pharmacol Biochem Behav. 1982 Mar;16(3):407-9. doi: 10.1016/0091-3057(82)90443-9.
The intrathecal (IT) injection of serotonin in the rat was found to produce a variety of behavioral signs of the serotonin "syndrome" as well as intense gnawing. Serotonin-induced gnawing is qualitatively similar to that evoked by tail pinch. Paradoxically, tail pinch-induced gnawing has been previously shown to be inhibited by serotonergic activity while we found a positive dose-related correlation between the IT administration of serotonin and gnawing. Pretreatment with methysergide IT completely blocked gnawing produced by intrathecally injected serotonin but not that evoked by tail pinch. In contrast, naloxone, reported to inhibit tail pinch-induced hyperphagia, failed to affect serotonin-induced gnawing. The parenteral injection of haloperidol inhibited both tail pinch-induced and serotonin-induced gnawing. Failure of intrathecally injected haloperidol to inhibit serotonin-induced gnawing indicates that dopamine mediates this behavior at a supraspinal level. The ability of serotonin to elicit gnawing when injected at the spinal cord level, but to inhibit the same behavior when evoked by tail pinch, suggest that this neurotransmitter plays opposite roles depending on which part of the CNS is involved.
在大鼠中发现，鞘内注射血清素会产生血清素“综合征”的各种行为迹象以及剧烈啃咬。血清素诱导的啃咬在性质上与夹尾引起的啃咬相似。矛盾的是，先前已证明夹尾诱导的啃咬会受到血清素能活性的抑制，而我们发现鞘内注射血清素与啃咬之间存在正剂量相关关系。鞘内注射美西麦角预处理可完全阻断鞘内注射血清素引起的啃咬，但不能阻断夹尾引起的啃咬。相比之下，据报道可抑制夹尾诱导的食欲亢进的纳洛酮，未能影响血清素诱导的啃咬。胃肠外注射氟哌啶醇可抑制夹尾诱导的和血清素诱导的啃咬。鞘内注射氟哌啶醇未能抑制血清素诱导的啃咬，这表明多巴胺在脊髓上水平介导这种行为。当在脊髓水平注射血清素时能够引发啃咬，但在夹尾引起时却抑制相同行为，这表明这种神经递质根据中枢神经系统的参与部位发挥相反的作用。
