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Fan-Rong Yao

Publications and source records attributed to Fan-Rong Yao.

3 recordsLinked to original sources
PubMed2006

Activation and sensitization of C and Adelta afferent fibers mediated by P2X receptors in rat dorsal skin.

The present study investigated the activation and sensitization effects of local injection of P2X receptor agonist alpha,beta-methylene ATP (alphabeta-meATP) into the receptive fields of afferent fibers innervating dorsal hairy skin in anesthetized rats. Single unit activities of afferent fibers were recorded by means of isolation of the fiber filaments from the dorsal cutaneous nerve branch. A total of 237 fibers were obtained. Of these, 67 were classed as C fibers, 104 as Adelta fibers and 66 as Abeta fibers. When alphabeta-meATP (0.1-100 microM, 10 microl) was injected subcutaneously into the receptive fields of these units, C and Adelta fibers demonstrated a dose-related increase in the discharge rates of the response. The activated proportion of C and Adelta fibers with a response to the drug also increased with dose. However, Abeta fibers did not exhibit significant activation. Furthermore, injection of alphabeta-meATP (10 microl) at a concentration of 100 microM resulted in a significant decrease of mechanical thresholds in C and Adelta fibers compared with pre-injection baseline (P < 0.05). In control experiments, injection of the vehicle phosphate-buffered saline (PBS, 10 microl) had no effect on all units tested. alphabeta-meATP (100 microM, 10 microl) followed by pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid (PPADS), a P2X receptor antagonist, successfully blocked the activation and sensitization effects of alphabeta-meATP on C and Adelta fibers tested. These results suggest that peripheral P2X receptors are involved in mediating peripheral excitation of C and Adelta fibers.

Action Potentials↗
PubMed2006

Electrophysiological evidence for the interaction of substance P and glutamate on Adelta and C afferent fibre activity in rat hairy skin.

1. The purpose of the present study was to investigate whether there was a cooperative interaction between substance P (SP) and glutamate (GLU) administered subcutaneously on Adelta and C primary afferent fibre activity in dorsal hairy skin of the rat in vivo. The single unit activities of Adelta and C afferent fibres were recorded by isolation of fibre filaments from the dorsal cutaneous nerve branches and the effects of subcutaneous injections of low doses of SP, GLU and SP + GLU on activity were determined. 2. Sub-threshold doses of SP (1 micro mol/L, 10 microL) administered subcutaneously into the dorsal hairy skin had no effect on the afferent discharges of either Adelta or C units. 3. The afferent discharges of 35% (11/31) of Adelta fibres and 33% (6/18) of C fibres were increased by local injection of the submaximal doses of GLU (10 micro mol/L, 10 microL) into the receptive fields. 4. The GLU-induced excitatory response was significantly enhanced by coinjection of subthreshold doses of SP. The mean discharge rates of Adelta fibres and C fibres were increased from 5.84 +/- 1.54 and 5.02 +/- 2.65 impulses/min to 19.91 +/- 4.35 and 17.58 +/- 5.59 impulses/min, respectively, whereas the excitatory proportions of Adelta and C fibres were increased from 35 and 33% to 84 and 83%, respectively. The duration of the excitation for Adelta fibres and C fibres was also significantly increased after coinjection of SP + GLU compared with that observed when either substance was given alone. 5. The present study provides electrophysiological evidence for an interaction between receptors for SP and GLU on the fine fibres activities in rat hairy skin, which may be involved in the mechanisms of hyperalgesia.

Animals↗