Malnutrition and REM-sleep Deprivation Modulate in Rats the Impairment of Spreading Depression by a Single Sub-convulsing Dose of Pilocarpine

Abstract

This study aimed to investigate the effect of a single injection of pilocarpine upon the phenomenon of cortical spreading depression (SD), in adult rats submitted to early malnutrition and/or to REM-sleep deprivation for 72 h prior to the SD-recordings. The SD was recorded continuously for 3-4 h in 13 well-nourished (W) and 15 early-malnourished (M) adult rats. One to two hours after the beginning of the recording session, a sub-convulsing intraperitoneal (i.p.) injection of pilocarpine (190 mg/kg) was applied and its effects on SD were studied during the rest of the recording session. Pilocarpine reduced markedly the ECoG amplitudes in all animals and decreased the SD velocity of propagation in the M-, but not in the W-rats, as compared with the pre-drug values for the same animals. In additional 9 W- and 10 M-animals, REM-sleep deprivation was induced during the 72 h preceding the SD-recording session. This condition enhanced the pilocarpine effects on SD in the W-, but not in the M-rats, as compared to the respective non-deprived (ND) groups. The results indicate an important acute cholinergic influence on SD, acting by means of pilocarpine-activated muscarinic receptors. This effect seems to be differentially modulated by sleep deprivation and malnutrition. * Present address: Departamento de Neurologia, Laboratório de Neurologia Aplicada e Experimental, FMRP/USP, CEP 14040-900, Ribeirão Preto, SP, Brazil † Present address: Recife Air Force Hospital, 50000-901 Recife, PE, Brazil

Keywords:

• Malnutrition
• Pilocarpine
• Spreading depression
• REM-sleep deprivation
• Cholinergic system