Janiri L, Falcone M, Persico A, Tempesta E
Department of Psychiatry, Catholic University, Faculty of Medicine, Rome, Italy.
J Neural Transm Gen Sect. 1991;86(2):135-46. doi: 10.1007/BF01250574.
Carnitine and acetylcarnitine have been demonstrated to be present in the CNS and to be involved in cholinergic mechanisms, even if their exact role in neurotransmission is still unknown. This microiontophoretic study was carried out on single cholinoceptive neurons of the somatosensory cortex in the rat in order to analyze the effects of L- and D-carnitine and L-acetylcarnitine on the spontaneous firing and the neuronal responses to some putative transmitters. L-carnitine and L-acetylcarnitine increased the spontaneous discharge rate, while D-carnitine was found to be ineffective. L-acetylcarnitine clearly potentiated the cholinergic excitatory responses. On the contrary, L-carnitine was found to reduce cholinergic responses in a great percentage of units and to inhibit L-acetylcarnitine-induced excitatory responses. Atropine blocked the increase in firing rate induced by L-carnitine and L-acetylcarnitine, thus suggesting for both of them a muscarinic activity. No interactions were observed between carnitines and GABA and glutamate. These results show that carnitine and acetylcarnitine are stereospecific neuroactive compounds with a cholinomimetic activity. They may play a role in a modulatory system for the cholinoceptive cortical neuron.
已证实肉碱和乙酰肉碱存在于中枢神经系统中，并参与胆碱能机制，尽管它们在神经传递中的确切作用仍不清楚。本微离子电泳研究针对大鼠体感皮层的单个胆碱能感受神经元进行，以分析左旋肉碱、右旋肉碱和左旋乙酰肉碱对自发放电以及神经元对某些假定递质反应的影响。左旋肉碱和左旋乙酰肉碱增加了自发放电率，而右旋肉碱则无效。左旋乙酰肉碱明显增强了胆碱能兴奋反应。相反，发现左旋肉碱在很大比例的单位中降低胆碱能反应，并抑制左旋乙酰肉碱诱导的兴奋反应。阿托品阻断了左旋肉碱和左旋乙酰肉碱诱导的放电率增加，因此表明它们两者都具有毒蕈碱活性。未观察到肉碱与γ-氨基丁酸和谷氨酸之间的相互作用。这些结果表明，肉碱和乙酰肉碱是具有拟胆碱活性的立体特异性神经活性化合物。它们可能在胆碱能感受性皮层神经元的调节系统中发挥作用。
