In vivo assessment of myocardial blood flow in rat heart using magnetic resonance imaging: Effect of anesthesia

Abstract

Purpose:To assess the influence of isoflurane and pentobarbital anesthesia and the carrier gases on myocardial blood flow (MBF) in the rat heart in vivo. Materials and Methods:MBF was quantified in vivo using arterial spin-labeling (ASL) magnetic resonance imaging (MRI). Left ventricular (LV) function was estimated during the same experiment using cine-MRI. Thirty-four male Wistar-Kyoto rats were divided in four groups, one anesthetized with isoflurane in oxygen:nitrous oxide mix (ISO), the three others with intraperitoneal pentobarbital, and breathing either room air (PB), oxygen:nitrous oxide (PB ϩ N 2 O), or oxygen:nitrogen (PB ϩ N 2 ).Results: MBF was significantly higher in the ISO and PB ϩ N 2 O groups vs. PB and in ISO vs. PB ϩ N 2 , with the following respective MBF values: ISO, 5.9 Ϯ 1.1; PB, 4.0 Ϯ 0.8; PB ϩ N 2 O, 5.1 Ϯ 1.4; and PB ϩ N 2 , 4.6 Ϯ 0.8 mL/g/minute, mean Ϯ SD. Ejection fractions were reduced by 10% in PB and PB ϩ N 2 O rats vs. ISO rats. Cardiac output (CO) and index (CI) were 25 to 30% lower in all rats anesthetized with pentobarbital than with isoflurane. Conclusion:Isoflurane and nitrous oxide induce a higher MBF than pentobarbital. Isoflurane also induces a higher ejection fraction in healthy rats.

Myocardial Perfusion Imaging is Feasible for Infarct Size Quantification in Mice Using a Clinical Single-photon Emission Computed Tomography System Equipped with Pinhole Collimators

“…Another limitation is presented by the missing record of heart frequency and temperature during anesthesia, which can certainly influence myocardial hemodynamics of mice. Blood flow in rat heart is reported to be higher during anesthesia with isoflurane or nitrous oxide than with pentobarbital [23]. For this reason, we avoid the use of inhalation anesthesia, employing instead medetomidine, midazolam, and fentanyl, which, in our experience, keeps the heart rate more stable than does xylazine and ketamine and, furthermore, has the advantage that it can be pharmacologically antagonized, so as to ensure recovery in longitudinal studies.…”

Severity of Locomotor and Cardiovascular Derangements after Experimental High-Thoracic Spinal Cord Injury Is Anesthesia Dependent in Rats

“…However, pentobarbital impairs the dynamics of respiratory and cardiovascular systems (Torbati et al, 1999;Walker et al, 1986;Webber and Peiss, 1979;Yamada et al, 1983). In prolonged anesthesia, pentobarbital has also been shown to impair myocardial contractility (Segel and Rendig, 1986), and to reduce myocardial blood flow and ejection fraction (Iltis et al, 2005). In addition, pentobarbital can progressively decrease body temperature through inhibition of brain metabolic activity (Kiyatkin and Brown, 2005) and decrease renal blood flow and glomerular filtration rate, probably mediated through the renin-angiotensin system (Walker et al, 1986).…”

“…Isoflurane is an inhalation anesthetic, producing rapid induction and recovery from anesthesia (half-life: 0-13 min) (Weightman, 2004). Similar to pentobarbital, isoflurane produces depression of the cardiovascular and respiratory systems (Fee and Thompson, 1997), however, this typically is mild and most studies report isoflurane to be a safe and reliable anesthetic with little negative effect on the cardiovascular and respiratory systems (Iltis et al, 2005;Szczesny et al, 2004). Compared to pentobarbital, in rats, isoflurane produces less deleterious cardiac effects, demonstrated by a higher mean coronary blood flow caused by a larger ejection fraction and higher cardiac output (Iltis et al, 2005).…”

“…Similar to pentobarbital, isoflurane produces depression of the cardiovascular and respiratory systems (Fee and Thompson, 1997), however, this typically is mild and most studies report isoflurane to be a safe and reliable anesthetic with little negative effect on the cardiovascular and respiratory systems (Iltis et al, 2005;Szczesny et al, 2004). Compared to pentobarbital, in rats, isoflurane produces less deleterious cardiac effects, demonstrated by a higher mean coronary blood flow caused by a larger ejection fraction and higher cardiac output (Iltis et al, 2005). As far as the authors are aware, this is the first study in which pentobarbital and isoflurane are compared and hemodynamic measurements are performed perioperatively in anesthetized animals, and chronically (2 weeks) in conscious spinal cord injured animals.…”

Chronic Hyperperfusion and Angiogenesis Follow Subacute Hypoperfusion in the Thalamus of Rats with Focal Cerebral Ischemia

“…A combination of isoflurane and nitrous oxide, which is a commonly used anesthesia, can increase baseline blood flow (Iltis et al, 2005). Also, 1% isoflurane dosed for 10 minutes invokes transient BBB opening in the thalamus of cats (Tetrault et al, 2008) and this likely occurs in rats.…”