title: Simultaneous measurement of arterial and left ventricular pressure in conscious freely moving rats by telemetry.
abstract: Comprehensive cardiovascular assessment in conscious rodents by utilizing telemetry has been limited by the restriction of current devices to one pressure channel. The purpose of this study was to test and validate a dual pressure transmitter that allows the simultaneous measurement of arterial pressure (AP) and left ventricular pressure (LVP) in conscious freely moving rats. Six rats were surgically implanted with dual pressure transmitters. Baseline hemodynamics and circadian rhythm were observed to return within 7days. AP, heart rate (HR), LVP and indices of left ventricular contractility were stable and demonstrated a prominent circadian rhythm over a two-week period of uninterrupted recordings. Administration of the vasodilator nifedipine produced the anticipated dose-dependent decrease in AP which was accompanied by a baroreflex mediated increase in HR and cardiac contractility. The negative inotrope verapamil produced the expected dose-dependent decreases in AP and cardiac contractility. Finally, a terminal validation of the dual pressure transmitter was performed under anesthesia by measuring AP and LVP simultaneously via telemetry and from a fluid filled arterial catheter and an intraventricular Millar catheter, respectively. A range of pressures and cardiac contractility were studied by administering sequential intravenous infusions of the positive inotrope dobutamine followed by verapamil. Linear regression analysis revealed a high level of agreement between pressures measured by the dual pressure transmitter and the exteriorized catheters. Histopathologic analysis of the heart revealed mild peri-catheter fibrosis. In conclusion, the simultaneous measurement of AP and LVP offers the potential for more detailed cardiovascular assessment in conscious rats.
authors.affiliation: Research and Development, Abbvie Inc., North Chicago, IL 60064, USA. Electronic address: jason.segreti@abbvie.com.
authors.forename: Jason A
authors.initials: JA
authors.lastname: Segreti
authors.affiliation: Research and Development, Abbvie Inc., North Chicago, IL 60064, USA.
authors.forename: James S
authors.initials: JS
authors.lastname: Polakowski
authors.affiliation: Research and Development, Abbvie Inc., North Chicago, IL 60064, USA.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Blomme
authors.affiliation: Research and Development, Abbvie Inc., North Chicago, IL 60064, USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: King
mesh_terms: D000818:Animals; D062186:Arterial Pressure / Q000502:physiology*; D003243:Consciousness / Q000187:drug effects / Q000502:physiology*; D004280:Dobutamine / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006352:Heart Ventricles / Q000187:drug effects / Q000503:physiopathology*; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology; D008297:Male; D023421:Models, Animal; D009200:Myocardial Contraction / Q000187:drug effects / Q000502:physiology; D009543:Nifedipine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013686:Telemetry / Q000379:methods; D014665:Vasodilator Agents / Q000494:pharmacology; D016277:Ventricular Function, Left / Q000187:drug effects / Q000502:physiology*; D017725:Ventricular Pressure / Q000187:drug effects / Q000502:physiology*; D014700:Verapamil / Q000494:pharmacology
chemical_list: D014665:Vasodilator Agents; D004280:Dobutamine; D014700:Verapamil; D009543:Nifedipine
keywords: Cardiovascular safety; Left-ventricular contractility; Rat; Telemetry