My works involve monitoring of QT and RR interval in albino rats. Due to lack of telemetry system I need to anethatise the animal prior to ECG recording. I seek for a robust anesthetic agent that would impart least impact on the heart rate, RR and QT interval. Kindly advise.
Etomidate (Hypnomidate) could be your drug of choice. It is a carboxylated imidazole anesthetic with minimal myocardial depressive effect. It was found to be a potent, short-acting and heart rate usually stays unchanged. Incidence of apnaea is also very low.
(ED50 = 0.57 mg/kg)
You may try Isofluorane. Very easy to administer via simple inhalation mask, fast acting (within 10 to 30 seconds), and fast recovery (within minute or so). Low level will give you a very good response for your intended purpose of ECG recording. I have published a paper on the safety of Isofluorane in avian patients. Let me know if you would like receiving a reprint.
Dr. Andrew.
We do not have small animal anesthesia setup, so we have to resort to injectables only.
Currently we use Ketamine+Xylazine; however, we are facing lots of reviewers' concern. Thus I am looking for alternative injectable methods.
The injectable anesthetic with lowest effect on heart rate will aid our purpose.
You may have a problem to fine injectable anesthetic that have no effect on cardiovascular system. First, any injection will create stress due to the handling of the animals and pain associated with injection. Pharmacological effects of stress factor (adrenaline) will persist for some time, and will affect the heart function. Inhalation anesthesia is superior to any other methods of anesthesia.
In your situation, I strongly suggest, consider inhalation anesthesia. For your purpose you do not need any sophisticated anesthetic equipment. Simple glass jar will serve you to anesthetise your rats just fine. Jar anesthesia is a common technique used in small rodents. You may find many protocols on the web. Attached is a protocol for mouse used at the University of Michigan. You should have no problem to scale it up for a rat.
Respected Dr. Andrew
Thanks sir.
This will be of great help. I am sure we can improvise and build a proper anesthetic cage with the protocol you've provided.