Neuroscience 2002 Abstract
| Presentation Number: | 737.9 |
|---|---|
| Abstract Title: | DIFFERENTIAL EFFECT OF CANNABINOID (CB) RECEPTOR AGONISTS ON RAT HIPPOCAMPAL NEURONAL ACTIVITY. |
| Authors: |
Mason, R.*1
; Roe, C.1
; Allen, C.1
1Sch Biomed Sci, Univ Nottingham Med Sch, Nottingham, United Kingdom |
| Primary Theme and Topics |
Synaptic Transmission and Excitability - Neurotransmitters -- Cannabinoids |
| Session: |
737. Neurotransmitters: cannabinoids I Poster |
| Presentation Time: | Wednesday, November 6, 2002 1:00 PM-2:00 PM |
| Location: | Hall A2-B3 C-48 |
| Keywords: | CANNABINOIDS, ELECTROPHYSIOLOGY, ANESTHESIA, MULTIELECTRODE |
C. Roe, C. Allen & R. Mason* School of Biomedical Sciences, University of Nottingham Medical School, Nottingham NG7 2UH, England.
Recent evidence supports the existence of a novel CB receptor in addition to CB1 receptors expressed in the hippocampus. The effects of the CB1/2 receptor agonists Δ-9-THC, CP55940, WIN55,212-2 and HU-210 were examined on firing activity of rat hippocampal neurones under different anaesthetic regimens.
Multiple single-unit extracellular activity was recorded from hippocampal CA1 & CA3 neurones in adult male Sprague-Dawley rats under urethane, halothane-N2O:O2 or isoflurane-N2O:O2 anaesthesia with multi-channel microwire electrode arrays (NBLabs, Tx) via a Plexon MAP system. Cannabinoid agonists (0.05-1mg.kg-1), the CB1 antagonist SR171614A (0.1mg.kg-1) or vehicle were administered i.v.
CB1 agonists produced a dose-dependent inhibition of firing in the majority of neurones recorded with a rank order WIN55,212-2 = CP55940 > Δ-9- THC; some neurones were either activated (∽20%) or unaffected (∽20%). WIN55,212-2 or CP55940-evoked responses were blocked by the CB1 antagonist SR171614A. At doses >0.05 mg.kg-1 HU210 (and, to a lesser degree, CP55940) caused respiratory depression in rats under halothane or isoflurane, but not with urethane anaesthesia. This interaction with gaseous anaesthetics was not observed for WIN55,212-2 or Δ-9-THC. In urethane anaesthetised rats, HU210 was found to be without effect in the hippocampus, yet induced (SR171614A-reversible) neuronal firing in the VTA. These data support the view of differential sensitivity of hippocampal neurones to cannabinoid agonists.
Recent evidence supports the existence of a novel CB receptor in addition to CB1 receptors expressed in the hippocampus. The effects of the CB1/2 receptor agonists Δ-9-THC, CP55940, WIN55,212-2 and HU-210 were examined on firing activity of rat hippocampal neurones under different anaesthetic regimens.
Multiple single-unit extracellular activity was recorded from hippocampal CA1 & CA3 neurones in adult male Sprague-Dawley rats under urethane, halothane-N2O:O2 or isoflurane-N2O:O2 anaesthesia with multi-channel microwire electrode arrays (NBLabs, Tx) via a Plexon MAP system. Cannabinoid agonists (0.05-1mg.kg-1), the CB1 antagonist SR171614A (0.1mg.kg-1) or vehicle were administered i.v.
CB1 agonists produced a dose-dependent inhibition of firing in the majority of neurones recorded with a rank order WIN55,212-2 = CP55940 > Δ-9- THC; some neurones were either activated (∽20%) or unaffected (∽20%). WIN55,212-2 or CP55940-evoked responses were blocked by the CB1 antagonist SR171614A. At doses >0.05 mg.kg-1 HU210 (and, to a lesser degree, CP55940) caused respiratory depression in rats under halothane or isoflurane, but not with urethane anaesthesia. This interaction with gaseous anaesthetics was not observed for WIN55,212-2 or Δ-9-THC. In urethane anaesthetised rats, HU210 was found to be without effect in the hippocampus, yet induced (SR171614A-reversible) neuronal firing in the VTA. These data support the view of differential sensitivity of hippocampal neurones to cannabinoid agonists.
Supported by GlaxoWellcome (UK), BBSRC & University of Nottingham
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2002 Neuroscience Meeting Planner. Orlando, FL: Society for Neuroscience, 2002. Online.
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