Aguiar LM, Macedo DS, de Freitas RM, de Albuquerque Oliveira A, Vasconcelos SMM, de Sousa FCF, de Barros Viana GS. Protective effects of N-acetylserotonin against 6-hydroxydopamine-induced neurotoxicity.
Life Sci 2005;
76:2193-202. [PMID:
15733934 DOI:
10.1016/j.lfs.2004.09.035]
[Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2004] [Accepted: 09/25/2004] [Indexed: 10/25/2022]
Abstract
The present work studied in vivo neuroprotective effects of n-acetylserotonin (NAS), the immediate precursor of melatonin, on the dopaminergic system, in rats lesioned with the unilateral intrastriatal injection of the neurotoxin 6-hydroxydopamine (6-OHDA). Two weeks after the lesion, the dopamine receptor agonist, apomorphine, produced rotational asymmetry, and the NAS treatment significantly reduced the motor deficit following the apomorphine challenge. The apomorphine-induced rotational behavior was blocked by 84, 86 and 53% after NAS, at doses of 2, 5 and 10 mg/kg, i.p., respectively. The injection of 6-OHDA significantly decreased DA, DOPAC and HVA levels in the rat striatum. In contrast, the NAS (2, 5 and 10 mg/kg, i.p., daily for 7 days) treatment partially reversed the decreases caused by 6-OHDA, and the neurotransmitter levels were brought to approximately 50% of that observed in the contralateral sides. NAS was more efficient at the smaller doses. NAS (5 mg/kg) produced an up-regulation of D1 (37%) and D2 (37%) receptors associated with a decrease in Kd values.
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