Spinal cord substance P mediates carbachol-induced cardiovascular responses from the rostral ventrolateral medulla.
Intrathecal (i.t.) infusion of substance P (SP) antagonist, (D-Pro2, D-Trp7,9)-substance P (20 micrograms), lowered blood pressure profoundly without any significant change of heart rate. The hypertensive and tachycardic responses elicited by microinjection of carbachol (25 ng/site) into the bilateral rostral ventrolateral medulla (rVLM) were blocked by i.t. infusion of SP antagonist. These data provided evidence that an excitatory cardiovascular effect induced by cholinergic system in rVLM may be mediated mainly by the SP receptors in spinal cord.
Department of Physiology, Shanghai Medical University, People's Republic of China.
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D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002217:Carbachol / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D007278:Injections, Spinal; D008526:Medulla Oblongata / Q000187:drug effects / Q000502:physiology*; D008845:Microinjections; D009411:Nerve Endings / Q000187:drug effects; D009474:Neurons / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D013116:Spinal Cord / Q000502:physiology*; D013373:Substance P / Q000502:physiology*
D013373:Substance P; D002217:Carbachol