单胺介质对四氢巴马汀引起的伏核单位放电抑制的影响

dl-四氢巴马汀(THP)能使大鼠伏核神经元的自发放电明显下降。本文观察脑室注射(icv)去甲肾上腺素(NA)、5-羟色胺(5-HT)和多巴胺(DA)对此抑制效应的影响。实验表明,在THP给药后30 min使伏核单位放电的抑制达峰值时icv NA(10μg/μl)能使伏核单位放电很快恢复,1 h后达给THP前水平。在给THP后30 min时,icv 5-HT(10 μg/μ1)对伏核单位放电的抑制并无影响。但在给THP后15 min伏核单位放电下降50%时,相同剂量5～HT则可使伏核单位放电的抑制作用逆转,1 h后和给THP前相似。给THP后30 min时icv DA(10 μg/μl),伏核单位的放电仍继续抑制。结果表明NA,5-HT能不同程度地对抗THP引起的伏核神经元的放电抑制效应,而DA对此抑制效应似乎并无影响。

INFLUENCE OF MONOAMINES ON THE DL-TETRAHYDROPALMATINE-INDUCED INHIBITION OF SINGLE-UNIT ACTIVITY IN THE NUCLEUS ACCUMBENS

dl-Tetrahydropalmatine (THP), a short-term monoamine depletor, has been found to be able to decrease the firing rate of the neurons in the nucleus accumbens (A). Influence of exogenous monoamines on the THP-induced inhibition of single-unit activity in A was studied by means of extracellular recording techniques in conscious rats immobilized by flaxedil. Intracerebroventricular (icv) administration of noradrenaline (NA, 10 μg/10 μl) reversed the depression of the firing in A induced by THP 30 rain after systematic injection. 5-Hydroxytryptamine (5-TH, 10 μg/ 10 μl) given icy produced a reversal of the depression of firing only by 50% 15 min after injection. While dopamine (DA, 10 μg/ 10 μl) showed no effect on the THP-induced inhibition.Our results indicate that NA and 5-TH, rather than DA, may be responsible for the THP-induced inhibition of single-unit activity in A.