Rivest R, Marsden C A
Department of Pharmacology, Medical School, University of Sherbrooke, Quebec, Canada.
Neuroscience. 1992;47(2):341-9. doi: 10.1016/0306-4522(92)90250-6.
The effect of scopolamine and atropine upon the increase in extracellular 3,4-dihydroxyphenylacetic acid induced by central injection of neurotensin was examined in the nucleus accumbens and the striatum of anaesthetized rats using in vivo differential pulse voltammetry with carbon fibre electrodes. Scopolamine (1 and 3 mg/kg, i.p.) and atropine (20 micrograms, i.c.v.) did not alter the 3,4-dihydroxyphenylacetic acid level in the nucleus accumbens or the striatum, measured for 60 min after administration. Neurotensin (10 micrograms, i.c.v.) increased the 3,4-dihydroxyphenylacetic acid peak height in both regions. Pretreatment with scopolamine (1 mg/kg) 15 min before neurotensin injection blocked the increase in extracellular 3,4-dihydroxyphenylacetic acid in the striatum but not in the nucleus accumbens whilst scopolamine (3 mg/kg) partially attenuated the effect of neurotensin in the nucleus accumbens and blocked the increase in 3,4-dihydroxyphenylacetic acid in the striatum. Atropine partially attenuated the effect produced by neurotensin in the nucleus accumbens and blocked the increase in 3,4-dihydroxyphenylacetic acid induced by the peptide in the striatum. However, the increase in extracellular 3,4-dihydroxyphenylacetic acid induced by haloperidol (1 mg/kg, s.c.) was not altered by scopolamine (1 mg/kg) or atropine. Also, the increase in dopamine metabolism in the nucleus accumbens and the striatum after centrally injected haloperidol (10 micrograms, i.c.v.) was not altered by atropine (20 micrograms, i.c.v.). Together, the results demonstrate a functional interaction between muscarinic antagonists and neurotensin on in vivo dopamine metabolism in the nucleus accumbens and the striatum but with a greater effect in the latter region.
在麻醉大鼠的伏隔核和纹状体中，使用碳纤维电极体内差分脉冲伏安法，研究了东莨菪碱和阿托品对中枢注射神经降压素诱导的细胞外3,4-二羟基苯乙酸增加的影响。东莨菪碱（1和3mg/kg，腹腔注射）和阿托品（20μg，脑室内注射）在给药后60分钟测量时，并未改变伏隔核或纹状体中的3,4-二羟基苯乙酸水平。神经降压素（10μg，脑室内注射）增加了两个区域的3,4-二羟基苯乙酸峰高。在注射神经降压素前15分钟用东莨菪碱（1mg/kg）预处理可阻断纹状体中细胞外3,4-二羟基苯乙酸的增加，但不影响伏隔核，而东莨菪碱（3mg/kg）部分减弱了神经降压素对伏隔核的作用，并阻断了纹状体中3,4-二羟基苯乙酸的增加。阿托品部分减弱了神经降压素在伏隔核中产生的作用，并阻断了该肽在纹状体中诱导的3,4-二羟基苯乙酸的增加。然而，氟哌啶醇（1mg/kg，皮下注射）诱导的细胞外3,4-二羟基苯乙酸的增加并未被东莨菪碱（1mg/kg）或阿托品改变。此外，脑室内注射氟哌啶醇（10μg）后伏隔核和纹状体中多巴胺代谢的增加并未被阿托品（20μg，脑室内注射）改变。总之，结果表明毒蕈碱拮抗剂与神经降压素在伏隔核和纹状体的体内多巴胺代谢上存在功能相互作用，但在后一区域的作用更大。
