Neuroscience 2002 Abstract
| Presentation Number: | 167.3 |
|---|---|
| Abstract Title: | Use of fos-GFP mice to detect <i>c-fos</i> activation in the isolated spinal cord preparation. |
| Authors: |
Dougherty, K. J.*1
; Sawchuk, M. A.1
; Hochman, S.1
1Dept Physiol, Emory Univ, Atlanta, GA |
| Primary Theme and Topics |
Motor Systems - Spinal Cord |
| Secondary Theme and Topics | Motor Systems<br />- Reflex Function |
| Session: |
167. Spinal cord: circuitry and network function Poster |
| Presentation Time: | Sunday, November 3, 2002 3:00 PM-4:00 PM |
| Location: | Hall A2-B3 K-3 |
| Keywords: | serotonin, dopamine, dorsal horn, activity labeling |
Activation of the immediate early gene c-fos has been used as a marker of CNS neuronal activity. The construction of a transgenic mouse employing green fluorescent protein (GFP) as a reporter of Fos expression (Quintero et al SFN Abst. 1999: 2065) allows for cell morphology of activated neurons to be visualized in both live and fixed tissue. These mice were obtained (D. McMahon, U Kentucky) to assess the utility of neurochemically-induced GFP expression in the in vitro intact spinal cord.
Mice (P4-20) were anesthetized before spinal cord isolation in aCSF. Following 3-5 hours, various drugs, including 5-HT, dopamine, strychnine, and bicuculline, were added for 2 hours and then cords were sectioned as fresh or fixed tissue. GFP was labeled with a polyclonal Rb antibody and compared to endogenous GFP fluorescence. Immunolabeled GFP was detectable in more neurons than observed with GFP fluorescence. Somata were clearly labeled and, in several neurons, processes were discernible. In all preparations, the substantia gelatinosa and medial deep dorsal horn contained many GFP-positive neurons, perhaps due to activation of nociceptors during surgical isolation procedures. Dopamine and 5-HT appeared to increase GFP labeling. In contrast, bicuculline and strychnine produced strong synchronous motor bursting but resulted in reduced staining, demonstrating that fos-GFP expression was not indicative of evoked activity.
We conclude that although fos-GFP expression labeled neurons in the in vitro mouse spinal cord, predominant staining appears nociception related. Procedures to report c-fos activation patterns selectively in response to drug-evoked motor activity have not yet been identified.
Mice (P4-20) were anesthetized before spinal cord isolation in aCSF. Following 3-5 hours, various drugs, including 5-HT, dopamine, strychnine, and bicuculline, were added for 2 hours and then cords were sectioned as fresh or fixed tissue. GFP was labeled with a polyclonal Rb antibody and compared to endogenous GFP fluorescence. Immunolabeled GFP was detectable in more neurons than observed with GFP fluorescence. Somata were clearly labeled and, in several neurons, processes were discernible. In all preparations, the substantia gelatinosa and medial deep dorsal horn contained many GFP-positive neurons, perhaps due to activation of nociceptors during surgical isolation procedures. Dopamine and 5-HT appeared to increase GFP labeling. In contrast, bicuculline and strychnine produced strong synchronous motor bursting but resulted in reduced staining, demonstrating that fos-GFP expression was not indicative of evoked activity.
We conclude that although fos-GFP expression labeled neurons in the in vitro mouse spinal cord, predominant staining appears nociception related. Procedures to report c-fos activation patterns selectively in response to drug-evoked motor activity have not yet been identified.
Supported by NIH #NS40440
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2002 Neuroscience Meeting Planner. Orlando, FL: Society for Neuroscience, 2002. Online.
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