ABSTRACT
A lesão do núcleo mediano da rafe (NMR) produz sintomas que sugerem validade de face ao episódio maníaco. Esta pesquisa avaliou o efeito do lítio sobre a hiperatividade locomotora induzida por esta lesão. Vinte e um ratos Wistar machos foram submetidos à lesão eletrolítica da região do NMR (LR) e 17 foram submetidos à lesão fictícia (LF). Após recuperação, a atividade locomotora foi avaliada na caixa de atividade (Med Associates/ENV-515). Parte dos animais destes grupos recebeu tratamentos com lítio (47,5 mg/kg/2x dia i.p.) por 10 dias, enquanto o restante foi tratado com salina no mesmo esquema. A reavaliação ao final dos tratamentos demonstrou que o lítio reduziu significantemente a atividade locomotora em relação à avaliação inicial no grupo LR (ANOVA/Bonferroni p < 0,05), tornando-a equivalente aos baixos níveis dos grupos LF. Estes dados sustentam a hipótese de que as manifestações induzidas pela lesão do NMR podem constituir um modelo animal de mania.
The lesion of the Median Raphe Nucleus (MRN) produces symptoms that suggest face validity for manic episodes. This research evaluated the effect of lithium treatment on the locomotor hyperactivity induced by this lesion. Twenty-one Wistar male rats were submitted to the lesion of the region of the MRN (LR) and 17 were sham lesioned (LF). After recovery, the locomotor activity was evaluated in an activity chamber (Med Associates/ENV-515). A subgroup received lithium (47.5 mg/kg/twice a day i.p.) for 10 days, while the other animals received saline in the same schedule. The reevaluation at the end of the treatments showed that only lithium significantly reduced the activity of LR group compared to baseline levels (ANOVA/Bonferroni p < 0.05), making it equivalent to low levels of LF groups. These data support the hypothesis that the behavioral manifestations induced by the lesion of the MRN may constitute an animal model of mania.
Subject(s)
Animals , Rats , Bipolar Disorder , Lithium/adverse effects , Models, Animal , Raphe Nuclei , Rats/injuriesABSTRACT
The different distributions of substance P(SP)-and leucine-enkephalin (L-ENK)-like immunoreactive neurons in the midbrain raphe nuclei of the rats have been studied, using PAP immunocytochemical technique. The results showed four main points: 1. SP-containing immunoreactive cell bodies were only seen in the most caudal part of the dorsal raphe nucleus, the average number of SP-positive cell bodies was about 167 in each animal. The L-ENK-like immunoreactive positive cell bodies were found almost in the whole length of the dorsal raphe nucleus, the L-ENK-positive cell bodies were about 132 in each animal. 2. L-ENK-Iike immunoreactive perikarya were mainly located in the midline area of the dorsal raphe nucleus. Besides the above areas, SP-containing immunoreactive cell bodies were also located bilaterally in the extended area from the raphe. 3. L-ENK-containing immunoreactive cell bodies constantly appeared in the median raphe nuclei, the average number was about 199 in each animal, but SP-containing immunoreactive bodies were only observed in this nucleus of two rats. 4. Some SP-like immunoreactive cell bodies or processes were observed in the vincinty of vascular walls, but the L-ENK positive neurons were not found similar results. The present experiment showed that the SP-like immunoreactive perikarya is located in the median raphe nuclei of the rat.