Intraperitoneal anaesthesia with propofol, medetomidine and fentanyl in mice

Abstract

Fast recoveries are essential when looking for a safe anaesthetic protocol to use on mice. Propofol is a short-acting anaesthetic agent, which provides a smooth, fast recovery. A recent study carried out in our laboratory showed that the intraperitoneal (i.p.) administration of propofol combined with a fast-acting opioid does not provide a sufficiently stable anaesthesia. In this experiment, we hypothesized that the additional application of medetomidine would increase muscle relaxation and analgesia. Fifty-four male CD1 mice, divided into six groups of five and three groups of eight, were used to test nine different combinations of propofol, medetomidine and fentanyl administered i.p. and reversed with atipamezole 30 min after induction. These combinations were composed in the following manner: propofol 75 mg/kg, medetomidine 1 and 2 mg/kg and fentanyl 0.1, 0.15 and 0.2 mg/kg. The depth of anaesthesia, loss of righting reflex, loss of pedal withdrawal reflex, pulse rate and respiratory rate were recorded along with the duration and quality of the recovery. The combination of propofol and medetomidine provided a predictable induction, hypnosis and muscle relaxation, but surgical anaesthesia (loss of pedal withdrawal reflex) was not achieved. The addition of fentanyl increased analgesia leading to surgical anaesthesia. We concluded that a combination of 75/1/0.2 mg/kg of propofol, medetomidine and fentanyl, respectively, is a safe, easy and reversible technique for i.p. anaesthesia in mice, providing a surgical window of 15 min and restraint for 30 min with a fast recovery.

Aloe-Emodin Relieves High-Fat Diet Induced QT Prolongation via MiR-1 Inhibition and IK1 Up-Regulation in Rats

“…Adult rats were anesthetized by intraperitoneal injection of sodium pentobarbital (40 mg/kg). The pedal withdrawal reflex (assessed by pinching the tail and the metacarpal region of the hind foot between the index finger and the thumb) was tested to assess the depth of anesthesia [22]. ECG recording was performed for 15 min every time.…”

Padronização e avaliação histológica de um modelo experimental de lesão medular

“…Esses efeitos estão relacionados com a dose e a velocidade de injeção e a incidência pode ser evitada através das seguintes medidas: injeção intravenosa lenta, uso de benzodiazepínicos na pré-medicação ou uso de relaxantes neuromusculares. Neste estudo, foi realizada a infusão lenta e a associação com um benzodiapénico, porém a ação do citrato de fentanila é curta (ALVES et al, 2010). Baseado no estudo de DAMY et al (2010), recomenda-se a substituição desse fármaco por buprenorfi na 0,02-0,5mg kg -1 SC, IP ou IM.…”

HPLC-UV method development for fentanyl determination in rat plasma and its application to elucidate pharmacokinetic behavior after i.p. administration to rats

“…Blood sampling after administration of FEN (0.1 mg/kg, i.p.) was held at 0, 10, 15, 20, 25, 30, 40, 90, 120 and 180 min, the used dose of FEN is consistent with previously reported method for rat treatment [11,12]. Blood was collected as previously explained, followed by spiking of 10 μL I.S.…”