Neuroscience 2004 Abstract
| Presentation Number: | 690.8 |
|---|---|
| Abstract Title: | Enkephalin-containing neurons in the central nucleus of the amygdala are activated by acute and chronic exposure to δ9-THC. |
| Authors: |
Morales, M.*1
; Diaz-Ruiz, O.1
; Roach, E.1
1IRP/NIDA/NIH/DHHS, Baltimore, MD |
| Primary Theme and Topics |
Synaptic Transmission and Excitability - Neurotransmitters -- Cannabinoids |
| Secondary Theme and Topics | Sensory Systems<br />- Anatomy |
| Session: |
690. Drugs of Abuse: Cannabinoids Poster |
| Presentation Time: | Tuesday, October 26, 2004 11:00 AM-12:00 PM |
| Location: | San Diego Convention Center - Hall A-H, Board # EEE10 |
| Keywords: |
Delta 9-tetrahydrocannabinol (Δ9-THC) is the active chemical in cannabis. To better understand the central effects of Δ9-THC, we sought to identify brain areas and neuronal populations responsive to acute and chronic administration of different doses of Δ9-THC. We used c-Fos positive immunoreactivity as a marker for Δ9-THC-responsive neurons. Acute Δ9-THC treatment. Rats were habituated to vehicle injections for 2 weeks, and killed two hours after receiving an IP injection on the 15th day of either vehicle or Δ9-THC (5 or 10 mg/kg). Brains were processed for immuno-detection of c-Fos. Δ9-THC induced c-Fos expression in the central nucleus of the amygdala (CNA). All rats treated with 10 mg/kg showed high levels of c-Fos expression, the lower dose (5 mg/kg) induced variability of c-Fos expression in the CAN. These results may indicate variability in the rat population in response to low doses of acute Δ9-THC. Chronic Δ9-THC treatment. Rats were injected for 2 weeks with daily single injections of 5 or 10 mg/kg of Δ9-THC. On the 15th day the animals received a final injection of either vehicle or Δ9-THC, and two hours later were killed. Rats injected with Δ9-THC displayed c-Fos immunoreactive neurons in the CAN. Individual variable levels of c-Fos immunoreactivity were observed in rats exposed to 10 mg/kg. In contrast, rats treated with 5 mg/kg showed less individual variability. These results may indicate variability in the rat population in response to different doses of chronic Δ9-THC. Phenotypic characterization of c-Fos immunoreactive neurons. By using a combination of in situ hybridization and immuno-histochemistry, we found that acute and chronic administration of Δ9-THC induced expression of c-Fos in neurons expressing pro-enkephalin (ENK).
Supported by IRP/NIDA/NIH/DHHS
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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