Electroencephalographic changes in response to electrical stimulation and acepromazine in minimally anaesthetised dogs

Yap, Coco (2023) Electroencephalographic changes in response to electrical stimulation and acepromazine in minimally anaesthetised dogs. [Project Paper] (Submitted)

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Abstract

Electroencephalography (EEG) has been reported as a tool to evaluate analgesic effect of centrally acting drugs in minimally anaesthetised animals. Notable increase in median frequency (MF) coupled with total power (Ptot) reduction were reported when animals experienced nociception. Most research found sedative analgesics and other centrally acting drugs prevent increase or even suppress MF in response to noxious stimulation. However, a question raised as effect MF associated with analgesia could be due to sedation caused by CNS depression. Acepromazine (ACE) is a phenothiazine having sedative but no analgesic effect. Therefore, this study aims to investigate the sedative effect of ACE on EEG in response to noxious electrical stimulus. Six dogs were subjected to incremental doses of ACE intravenously (IV), starting from 0.05 mg/kg, followed by 0.1 mg/kg and 0.2 mg/kg with interval of 20 minutes. Anaesthesia was induced with propofol at 5 mg/kg IV and maintained with halothane at stable concentration between 0.85 to 0.95% (Minimal Anaesthesia Model). Noxious electrical stimulus was delivered with a peripheral nerve stimulator N272 at 40 mA and 50 Hz for 5 seconds. Each animal served as its own control. Baseline EEG was recorded before any ACE or noxious electrical stimulation. EEG were recorded prior to ACE and following ACE during noxious electrical stimulation. Result showed that post-stimulation MF increased significantly (p < 0.05) in all treatment groups. In contrast, there was no significant (p > 0.05) difference in post-stimulation Ptot in all treatment groups. Thus, ACE neither suppressed nor prevented increase in MF and has no effect on Ptot in response to noxious electric stimulus. MF is associated with nociception, whereas Ptot does not. It is concluded that analgesic effect of the centrally acting agents expressed by MF of EEG may not be due to sedation.

Item Type:	Project Paper
Faculty:	Faculty of Veterinary Medicine
Depositing User:	Ms Nurhaznita Mahmood
Date Deposited:	30 Sep 2024 06:59
Last Modified:	30 Sep 2024 06:59
URI:	http://psaspb.upm.edu.my/id/eprint/2074

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