Endocannabinoid-dependent plasticity at spinal nociceptor synapses
| Autor: | Kato, Ako, Punnakkal, Pradeep, Pernía-Andrade, Alejandro Javier, von Schoultz, Carolin, Sharopov, Salim, Nyilas, Rita, Katona, István, Zeilhofer, Hanns Ulrich |
|---|---|
| Přispěvatelé: | University of Zurich, Zeilhofer, Hanns Ulrich |
| Jazyk: | angličtina |
| Rok vydání: | 2012 |
| Předmět: |
Male
Neuronal Plasticity musculoskeletal neural and ocular physiology Excitatory Postsynaptic Potentials Nociceptors 10050 Institute of Pharmacology and Toxicology Mice Transgenic 610 Medicine & health 1314 Physiology In Vitro Techniques Neuroscience: Cellular/Molecular Mice nervous system Receptor Cannabinoid CB1 Spinal Cord Synapses Animals 570 Life sciences biology lipids (amino acids peptides and proteins) Female Endocannabinoids |
| Zdroj: | Journal of Physiology The Journal of Physiology |
| Popis: | Neuroplastic changes at the spinal synapses between primary nociceptors and second order dorsal horn neurons play key roles in pain and analgesia. NMDA receptor-dependent forms of long-term plasticity have been studied extensively at these synapses, but little is known about possible contributions of the endocannabinoid system. Here, we addressed the role of cannabinoid (CB)1 receptors in activity-dependent plasticity at these synapses. We report that conditional low-frequency stimulation of high-threshold primary sensory nerve fibres paired with depolarisation of the postsynaptic neuron evoked robust long-term depression (LTD)of excitatory synaptic transmission by about 40% in the vast majority (90%) of recordings made in wild-type mice. When recordings were made from global or nociceptor-specific CB(1) receptor-deficient mice (CB(1) (−/− ) mice and sns-CB(1)(−/−) mice), the portion of neurons exhibiting LTD was strongly reduced to about 25%. Accordingly, LTD was prevented to a similar extent by the CB1 receptor antagonist AM251 and mimicked by pharmacological activation of CB1 receptors. In a subset of neurons with EPSCs of particularly high stimulation thresholds, we furthermore found that the absence of CB(1) receptors in CB(1)(−/−) and sns-CB(1)(−/−) mice converted the response to the paired conditioning stimulation protocol from LTD to long-term potentiation (LTP). Our results identify CB1 receptor-dependent LTD as a form of synaptic plasticity previously unknown in spinal nociceptors. They furthermore suggest that prevention of LTP may be a second hither to unknown function of CB1 receptors in primary nociceptors. Both findings may have important implications for our understanding of endogenous pain control mechanisms and of analgesia evoked by cannabinoid receptor agonists. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|