[Effects of intracarotid injection of capsaicin on electrical activity of rostral ventrolateral medullary neurons in rats].
The effects of intracarotid injection of capsaicin on spontaneous electrical activity of nucleus paragigantocellularis lateralis (PGL) neurons in rostral ventrolateral medulla (RVLM) were examined in 35 anesthetized rats with sino-aortic denervation by using extracellular recording technique. The results obtained were as follows: (1) In response to intracarotid injection of capsaicin (10 mumol, 0.1 ml), MAP was increased from 10.74 +/- 0.13 to 12.56 +/- 0.21 kPa (P < 0.001), and HR from 374 +/- 4 to 395 +/- 5 bpm (P < 0.001). All of 30 PGL neurons recorded responded to intracarotid injection of capsaicin with an increase in spontaneous discharge rate from 12.6 +/- 0.7 to 20.9 +/- 1.1 spikes/s (P < 0.001); (2) In 10 units, the excitatory response of PGL neurons to intracarotid injection of capsaicin was significantly inhibited by pretreatment with the vanilloid receptor (capsaicin receptor) antagonist ruthenium red (200 mmol, 0.1 ml). These results suggest that capsaicin may stimulate the vanilloid receptor of neurons in RVLM, thereby resulting in activation of PGL neurons.
Xue
B J
BJ
Department of Physiology, Institute of Basic Medicine, Hebei Medical University, Shijiazhuang 050017.
He
R R
RR
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002211:Capsaicin / Q000494:pharmacology*; D002339:Carotid Arteries; D004594:Electrophysiology; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D007269:Injections, Intra-Arterial; D008297:Male; D008526:Medulla Oblongata / Q000502:physiology*; D008839:Microelectrodes; D009474:Neurons / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011955:Receptors, Drug / Q000037:antagonists & inhibitors; D012430:Ruthenium Red / Q000494:pharmacology
D011955:Receptors, Drug; D012430:Ruthenium Red; D002211:Capsaicin