Effects of pinealectomy and the treatment with melatonin on the temporal lobe epilepsy in rats.
The aim of the present work was to analyze the effects of pinealectomy in the development of the epilepsy model induced by pilocarpine in adult male rats. Group I: Wistar male adult rats were submitted to pinealectomy, and 7 days after surgery, these animals received pilocarpine (350 mg/kg, i.p.) to induce three distinct behavioral phases: status epilepticus, seizure-free, and chronic phases. This late, as well as all control groups were continuously video-recorded for 60 days, to study behavior parameters. These animals were killed and the brain sections were processed for Nissl and neo-Timm. Group II: Another group, also submitted to pinealectomy, received several injections of melatonin (2.5 mg/kg): 20 min before, concomitantly with pilocarpine, 30 min, 1 h, and 2 h after pilocarpine administration. Some animals from group I and all from group II were sacrificed 48 h following status epilepticus onset to perform TUNEL assay. The latency for status epilepticus onset, status epilepticus length as well as mortality rate during status epilepticus were similar for pinealectomized and control groups. On the other hand, pinealectomized rats presented minor duration of the silent period, a higher number of spontaneous seizures during the chronic phase, increased number of TUNEL-positive cells (acute phase), increased neuronal loss, and marked supragranullar mossy fibers sprouting (chronic phase) in the hippocampal formation, when compared with control groups. Our data show that the pinealectomy facilitates the epileptogenic process that follows the long-lasting status epilepticus. This facilitation can be partially reverted by the simultaneous administration of melatonin.
de Lima
Eliângela
E
Disciplina de Neurologia Experimental, Universidade Federal de São Paulo-Escola Paulista de Medicina, CEP 04023-900, Edifício Leal Prado, São Paulo, SP, Brazil.
Soares
José Maria
JM
del Carmen Sanabria Garrido
Yaima
Y
Gomes Valente
Sandra
S
Priel
Margareth Rose
MR
Chada Baracat
Edmund
E
Abrão Cavalheiro
Esper
E
da Graça Naffah-Mazzacoratti
Maria
M
Amado
Débora
D
D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D003714:Denervation; D004195:Disease Models, Animal; D004833:Epilepsy, Temporal Lobe / Q000139:chemically induced / Q000188:drug therapy* / Q000503:physiopathology*; D006624:Hippocampus / Q000473:pathology; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D018721:Muscarinic Agonists; D010862:Pilocarpine; D010870:Pineal Gland / Q000502:physiology / Q000601:surgery*; D051381:Rats; D017208:Rats, Wistar; D013226:Status Epilepticus / Q000139:chemically induced / Q000188:drug therapy / Q000503:physiopathology
D000927:Anticonvulsants; D018721:Muscarinic Agonists; D010862:Pilocarpine; D008550:Melatonin