title: Age-related change in the effect of gentle mechanical cutaneous stimulation on the somato-cardiac sympathetic C-reflex.
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.
authors.affiliation: Department of Autonomic Neuroscience, Tokyo Metropolitan Institute of Gerontology, Sakae-cho, Itabashi-ku, Japan.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Watanabe
authors.forename: Sae
authors.initials: S
authors.lastname: Uchida
authors.forename: Harumi
authors.initials: H
authors.lastname: Hotta
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D017704:Baroreflex / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D004558:Electric Stimulation; D005260:Female; D006321:Heart / Q000294:innervation*; D009270:Naloxone / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D010812:Physical Stimulation; D051381:Rats; D017208:Rats, Wistar; D012018:Reflex / Q000187:drug effects / Q000502:physiology*; D013564:Sympathetic Nervous System / Q000502:physiology*; D013848:Thigh / Q000294:innervation*; D013979:Tibial Nerve / Q000502:physiology; D014110:Touch / Q000502:physiology*
chemical_list: D010656:Phenylephrine; D009270:Naloxone