Peripheral afferent mechanisms underlying acupuncture inhibition of cocaine behavioral effects in rats

PLoS One. 2013 Nov 18;8(11):e81018. doi: 10.1371/journal.pone.0081018. eCollection 2013.

Abstract

Administration of cocaine increases locomotor activity by enhancing dopamine transmission. To explore the peripheral mechanisms underlying acupuncture treatment for drug addiction, we developed a novel mechanical acupuncture instrument (MAI) for objective mechanical stimulation. The aim of this study was to evaluate whether acupuncture inhibition of cocaine-induced locomotor activity is mediated through specific peripheral nerves, the afferents from superficial or deep tissues, or specific groups of nerve fibers. Mechanical stimulation of acupuncture point HT7 with MAI suppressed cocaine-induced locomotor activity in a stimulus time-dependent manner, which was blocked by severing the ulnar nerve or by local anesthesia. Suppression of cocaine-induced locomotor activity was elicited after HT7 stimulation at frequencies of either 50 (for Meissner corpuscles) or 200 (for Pacinian corpuscles) Hz and was not affected by block of C/Aδ-fibers in the ulnar nerve with resiniferatoxin, nor generated by direct stimulation of C/Aδ-fiber afferents with capsaicin. These findings suggest that HT7 inhibition of cocaine-induced locomotor activity is mediated by A-fiber activation of ulnar nerve that originates in superficial and deep tissue.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acupuncture Points
  • Acupuncture Therapy*
  • Afferent Pathways / drug effects*
  • Afferent Pathways / physiopathology
  • Animals
  • Behavior, Animal / drug effects
  • Capsaicin / pharmacology
  • Cocaine-Related Disorders / physiopathology
  • Cocaine-Related Disorders / therapy*
  • Diterpenes / pharmacology
  • Electric Stimulation
  • Locomotion / drug effects
  • Male
  • Nerve Fibers, Myelinated / drug effects
  • Nerve Fibers, Unmyelinated / drug effects
  • Rats
  • Rats, Sprague-Dawley
  • Sensory System Agents / pharmacology
  • Ulnar Nerve / drug effects

Substances

  • Diterpenes
  • Sensory System Agents
  • resiniferatoxin
  • Capsaicin