Neuroscience 2005 Abstract
| Presentation Number: | 189.17 |
|---|---|
| Abstract Title: | M1 receptor activation in the rat: a phMRI analysis. |
| Authors: |
Bird, S. B.*1,2
; Schmidt, K.2
; Kulkarni, P.3
; Ferris, C.2
1Dept. of Emergency Medicine, Univ. of Massachusetts Medical School, Univ. of Massachusetts, Worcester, MA 2Center for Comparative Neuroimaging, Univ. of Massachusetts, Worcester, MA 3MA, 55 Lake Ave North, 01655, |
| Primary Theme and Topics |
Homeostatic and Neuroendocrine Systems - Brain Blood Flow, Metabolism and Homeostasis -- Functional imaging |
| Session: |
189. Blood Flow and Functional Imaging Poster |
| Presentation Time: | Sunday, November 13, 2005 8:00 AM-9:00 AM |
| Location: | Washington Convention Center - Hall A-C, Board # HH29 |
| Keywords: |
Background: The ubiquitous nature and profound physiologic effects of muscarinic receptors in the brain has limited the ability of functional magnetic resonance imaging (fMRI) to detect activations of the acetylcholine system. Pharmacological MRI (phMRI) using Blood Oxygen Level Dependent (BOLD) and cerebral blood flow (CBF) methods were developed to spatially identify muscarinic subtype-1 receptor activation in the rat. Objective: to spatially identify the M1 receptor activation using phMRI with the selective M1 agonist McN-A-343 in the rat. Methods: Male Wistar rats were imaged with a Bruker 4.7T magnet using both echo planar imaging with continuous arterial spin labeling and with fast spin echo techniques. In order to obtain dose-response curves, various doses (0.04 to 4.0 mg/kg) (n=6 per dose) of the selective M1 receptor agonist McN-A-343 were given IV. Heart rate, arterial blood pressure, and respiratory rate were continuously recorded. Placebo injections were performed before the study drug. Data were analyzed using AFNI and MIVA. Results: Doses of McN-A-343 greater than 0.4 mg/kg induced hemodynamic changes that precluded phMRI evaluation. Lower doses had no hemodynamic or respiratory effects. Functional maps generated using CBF and BOLD demonstrated activation primarily in the hippocampus and striatum. Conclusions: phMRI using BOLD and CBF imaging can spatially detect activation of the specific muscarinic receptor subtype-1. M1 receptor activation was evident predominantly within the hippocampus and striatum, concordant with histological studies.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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