Age-related change in the effect of gentle mechanical cutaneous stimulation on the somato-cardiac sympathetic C-reflex

J Physiol Sci. 2011 Jul;61(4):287-91. doi: 10.1007/s12576-011-0146-y. Epub 2011 Apr 9.

Abstract

This study examined whether aging influences the effect of gentle mechanical cutaneous stimulation (touch) on somato-cardiac sympathetic reflexes in anesthetized rats. A single electrical stimulus (15 V, 0.5 ms) applied to the tibial nerve induced somato-cardiac sympathetic A- and C-reflexes, which originated from the myelinated A- and unmyelinated C-fibers of the tibial nerve, respectively. When touch was applied to the inner thigh ipsilateral to the electrical stimulation, the C-reflex was selectively inhibited in adult rats (4-12 months), and this response was abolished by the opioid receptor antagonist, naloxone. Such an inhibitory effect of touch was impaired in aged rats (26-30 months). In contrast, depression of both A- and C-reflexes during a phenylephrine-induced rise in blood pressure was well maintained in the aged group. This study indicates that activation of the opioidergic system by gentle mechanical cutaneous stimulation attenuates with aging.

MeSH terms

  • Aging / physiology*
  • Animals
  • Baroreflex / physiology
  • Blood Pressure / drug effects
  • Blood Pressure / physiology
  • Electric Stimulation
  • Female
  • Heart / innervation*
  • Naloxone / pharmacology
  • Phenylephrine / pharmacology
  • Physical Stimulation
  • Rats
  • Rats, Wistar
  • Reflex / drug effects
  • Reflex / physiology*
  • Sympathetic Nervous System / physiology*
  • Thigh / innervation*
  • Tibial Nerve / physiology
  • Touch / physiology*

Substances

  • Phenylephrine
  • Naloxone