Neuroscience 2004 Abstract
| Presentation Number: | 380.11 |
|---|---|
| Abstract Title: | Functional magnetic resonance imaging (fMRI) in rats following m-chlorophenylpiperazine. |
| Authors: |
Stark, J. A.*1
; Davies, K. E.2
; Williams, S. R.2
; Luckman, S. M.1
1Sch. of Biological Sci., Univ Manchester, Manchester, United Kingdom 2United Kingdom, Stopford Building, Oxford Road, M13 9PT, |
| Primary Theme and Topics |
Homeostatic and Neuroendocrine Systems - Regulation of Food Intake and Body Weight -- Monamines, amino acids and other regulators |
| Secondary Theme and Topics | Homeostatic and Neuroendocrine Systems<br />- Regulation of Food Intake and Body Weight<br />-- Central pathways - anatomy and development |
| Session: |
380. Signaling, Development, and Anatomy Slide |
| Presentation Time: | Monday, October 25, 2004 10:30 AM-10:45 AM |
| Location: | San Diego Convention Center - Room 32B |
| Keywords: | food intake, obesity, serotonin |
We are developing fMRI to characterise common homeostatic and reward pathways of drugs and natural regulators of appetite. As a proof of concept, an anorexic dose of the 5-HT2C/1B receptor agonist m-chlorophenylpiperazine (mCPP; 3mg/kg s.c.) was used to compare fMRI with expression of the c-Fos protein. mCPP was injected into satiated male Sprague-Dawley rats, which were then anaesthetised and perfused transcardially 90 min later to allow immunocytochemistry. In a separate experiment, rats underwent fMRI in a 7 Tesla magnet for 70 min under α-chloralose anaesthesia. A T2* weighted gradient echo was used to record brain volumes every 70 s. Results, analysed using SPM99 software, determined brain areas with significant changes in Blood Oxygenation Level Dependent (BOLD) contrast.
Both methods detected activity in areas of the limbic system: nucleus accumbens, medial hypothalamus, bed nucleus of the stria terminalis, and thalamus. fMRI detected activation in the pontine nuclei, the hippocampal formation and some other cortical regions, areas that did not display c-Fos. In addition, BOLD signal was diminished in the ventral tegmental area, preoptic area, and the cerebellum - presumably due to decreased neuronal signalling and, therefore, area unlikely to display induced c-Fos.
Activity in the limbic system may reflect the appetitive agonist activity of mCPP at the 5-HT2C receptor. Non-selective agonism at 5-HT1B receptors may result in the established hypolocomotive side effect of mCPP. We conclude that c-Fos provides excellent spatial information, but is less useful for detecting inhibited regions. C-Fos is not always linked directly to electrical activity, which might explain the presence of BOLD signals in areas not containing c-Fos. Thus, the two methodologies provide complementary details of brain activity following pharmacological challenge.
Both methods detected activity in areas of the limbic system: nucleus accumbens, medial hypothalamus, bed nucleus of the stria terminalis, and thalamus. fMRI detected activation in the pontine nuclei, the hippocampal formation and some other cortical regions, areas that did not display c-Fos. In addition, BOLD signal was diminished in the ventral tegmental area, preoptic area, and the cerebellum - presumably due to decreased neuronal signalling and, therefore, area unlikely to display induced c-Fos.
Activity in the limbic system may reflect the appetitive agonist activity of mCPP at the 5-HT2C receptor. Non-selective agonism at 5-HT1B receptors may result in the established hypolocomotive side effect of mCPP. We conclude that c-Fos provides excellent spatial information, but is less useful for detecting inhibited regions. C-Fos is not always linked directly to electrical activity, which might explain the presence of BOLD signals in areas not containing c-Fos. Thus, the two methodologies provide complementary details of brain activity following pharmacological challenge.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2004 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2004. Online.
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