Vagal afferent modulation of a nociceptive reflex in rats: involvement of spinal opioid and monoamine receptors

Academic Article


  • Modulation of the spinal nociceptive tail flick (TF) reflex by electrical stimulation of subdiaphragmatic or cervical vagal afferent fibers was characterized in rats lightly anesthetized with pentobarbital. Cervical vagal afferent stimulation (VAS) inhibited the TF reflex in a pulse width-, frequency-, and intensity-dependent fashion. The optimum parameters for inhibition of the TF reflex were determined to be 2.0 ms pulse width, 20 Hz frequency with a threshold (T) current of 60 μA. Cervical VAS at 0.2-0.6 T facilitated the TF reflex. Cervical VAS at T typically produced a depressor arterial blood pressure response, but inhibition of the TF reflex by VAS was not due to changes in blood pressure. Subdiaphragmatic VAS also inhibited the TF reflex and generally produced a pressor effect, but did not facilitate the TF reflex at intensities of stimulation
  • Authors

    Published In

  • Brain Research  Journal
  • Digital Object Identifier (doi)

    Author List

  • Ren K; Randich A; Gebhart GF
  • Start Page

  • 285
  • End Page

  • 294
  • Volume

  • 446
  • Issue

  • 2