title: Substance P released endogenously by high-intensity sensory stimulation potentiates purinergic inhibition of nociceptive dorsal horn neurons induced by peripheral vibration.
abstract: To investigate the interaction at the spinal level of endogenously released substance P with the effects of endogenously released adenosine, extracellular single-unit activity was recorded from dorsal horn neurons in the anesthetized cat. Vibration to the skin inhibited on-going activity of nociceptive neurons; 20 mg/kg caffeine reversibly blocked this inhibition, indicating mediation via adenosine receptors. In half of the cases, this inhibition was potentiated by iontophoretic application of substance P. High-intensity electrical stimulation to a sensory nerve produced excitation which was blocked by an NK-1 (substance P) receptor antagonist, implicating an endogenous neurokinin. When electrical stimulation preceded the vibrational stimulus, the inhibitory effect of vibration was potentiated. Thus, we suggest that endogenous substance P may potentiate the inhibitory response to endogenous adenosine. The results have important implications for integration of inputs from different sensory modalities, especially as they relate to nociception and pain.
authors.affiliation: Department of Physiology, McGill University, Montréal, Québec, Canada.
authors.forename: Y
authors.initials: Y
authors.lastname: De Koninck
authors.forename: M W
authors.initials: MW
authors.lastname: Salter
authors.forename: J L
authors.initials: JL
authors.lastname: Henry
mesh_terms: D000818:Animals; D001713:Biphenyl Compounds / Q000494:pharmacology; D002110:Caffeine / Q000494:pharmacology*; D002415:Cats; D004558:Electric Stimulation; D004594:Electrophysiology / Q000379:methods; D018698:Glutamic Acid / Q000494:pharmacology; D006993:Hypnotics and Sedatives / Q000494:pharmacology; D007478:Iontophoresis; D009474:Neurons / Q000502:physiology*; D010525:Peripheral Nerves / Q000502:physiology*; D012867:Skin / Q000294:innervation; D013116:Spinal Cord / Q000502:physiology*; D013373:Substance P / Q000008:administration & dosage / Q000494:pharmacology* / Q000502:physiology*; D013997:Time Factors; D014732:Vibration
chemical_list: D001713:Biphenyl Compounds; D006993:Hypnotics and Sedatives; D013373:Substance P; D002110:Caffeine; D018698:Glutamic Acid; C066892:CP 96345