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Cannabinoid-induced presynaptic inhibition of glutamatergic EPSCs in substantia gelatinosa neurons of the rat spinal cord.
J Neurophysiol. 2001 Jul; 86(1):40-8.JN

Abstract

The effect of cannabinoids on excitatory transmission in the substantia gelatinosa was investigated using intracellular recording from visually identified neurons in a transverse slice preparation of the juvenile rat spinal cord. In the presence of strychnine and bicuculline, perfusion of the cannabinoid receptor agonist WIN55,212-2 reduced the frequency and the amplitude of spontaneous excitatory postsynaptic currents (sEPSCs). Furthermore, the frequency of miniature EPSCs (mEPSCs) was also decreased by WIN55,212-2, whereas their amplitude was not affected. Similar effects were reproduced using the endogenous cannabinoid ligand anandamide. The effects of both agonists were blocked by the selective CB(1) receptor antagonist SR141716A. Electrical stimulation of high-threshold fibers in the dorsal root evoked a monosynaptic EPSC in lamina II neurons. In the presence of WIN55,212-2, the amplitude of the evoked EPSC (eEPSCs) was reduced, and the paired-pulse ratio was increased. The reduction of the eEPSC following CB(1) receptor activation was unlikely to have a postsynaptic origin because the response to AMPA, in the presence of 1 microM TTX, was unchanged. To investigate the specificity of this synaptic inhibition, we selectively activated the nociceptive C fibers with capsaicin, which induced a strong increase in the frequency of EPSCs. In the presence of WIN55,212-2, the response to capsaicin was diminished. In conclusion, these results strongly suggest a presynaptic location for CB(1) receptors whose activation results in inhibition of glutamate release in the spinal dorsal horn. The strong inhibitory effect of cannabinoids on C fibers may thereby contribute to the modulation of the spinal excitatory transmission, thus producing analgesia at the spinal level.

Authors+Show Affiliations

Novartis, London WC1E 6BN, United Kingdom.No affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

11431486

Citation

Morisset, V, and L Urban. "Cannabinoid-induced Presynaptic Inhibition of Glutamatergic EPSCs in Substantia Gelatinosa Neurons of the Rat Spinal Cord." Journal of Neurophysiology, vol. 86, no. 1, 2001, pp. 40-8.
Morisset V, Urban L. Cannabinoid-induced presynaptic inhibition of glutamatergic EPSCs in substantia gelatinosa neurons of the rat spinal cord. J Neurophysiol. 2001;86(1):40-8.
Morisset, V., & Urban, L. (2001). Cannabinoid-induced presynaptic inhibition of glutamatergic EPSCs in substantia gelatinosa neurons of the rat spinal cord. Journal of Neurophysiology, 86(1), 40-8.
Morisset V, Urban L. Cannabinoid-induced Presynaptic Inhibition of Glutamatergic EPSCs in Substantia Gelatinosa Neurons of the Rat Spinal Cord. J Neurophysiol. 2001;86(1):40-8. PubMed PMID: 11431486.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Cannabinoid-induced presynaptic inhibition of glutamatergic EPSCs in substantia gelatinosa neurons of the rat spinal cord. AU - Morisset,V, AU - Urban,L, PY - 2001/6/30/pubmed PY - 2001/8/31/medline PY - 2001/6/30/entrez SP - 40 EP - 8 JF - Journal of neurophysiology JO - J Neurophysiol VL - 86 IS - 1 N2 - The effect of cannabinoids on excitatory transmission in the substantia gelatinosa was investigated using intracellular recording from visually identified neurons in a transverse slice preparation of the juvenile rat spinal cord. In the presence of strychnine and bicuculline, perfusion of the cannabinoid receptor agonist WIN55,212-2 reduced the frequency and the amplitude of spontaneous excitatory postsynaptic currents (sEPSCs). Furthermore, the frequency of miniature EPSCs (mEPSCs) was also decreased by WIN55,212-2, whereas their amplitude was not affected. Similar effects were reproduced using the endogenous cannabinoid ligand anandamide. The effects of both agonists were blocked by the selective CB(1) receptor antagonist SR141716A. Electrical stimulation of high-threshold fibers in the dorsal root evoked a monosynaptic EPSC in lamina II neurons. In the presence of WIN55,212-2, the amplitude of the evoked EPSC (eEPSCs) was reduced, and the paired-pulse ratio was increased. The reduction of the eEPSC following CB(1) receptor activation was unlikely to have a postsynaptic origin because the response to AMPA, in the presence of 1 microM TTX, was unchanged. To investigate the specificity of this synaptic inhibition, we selectively activated the nociceptive C fibers with capsaicin, which induced a strong increase in the frequency of EPSCs. In the presence of WIN55,212-2, the response to capsaicin was diminished. In conclusion, these results strongly suggest a presynaptic location for CB(1) receptors whose activation results in inhibition of glutamate release in the spinal dorsal horn. The strong inhibitory effect of cannabinoids on C fibers may thereby contribute to the modulation of the spinal excitatory transmission, thus producing analgesia at the spinal level. SN - 0022-3077 UR - https://www.unboundmedicine.com/medline/citation/11431486/Cannabinoid_induced_presynaptic_inhibition_of_glutamatergic_EPSCs_in_substantia_gelatinosa_neurons_of_the_rat_spinal_cord_ L2 - https://journals.physiology.org/doi/10.1152/jn.2001.86.1.40?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -