Title
A Selective NK1 Tachykinin Receptor Agonist and Substance P (SP) Have Similar Effects on Sympathetic Ganglia, Blood Pressure and Heart Rate of Normotensive and Hypertensive Rats
Document Type
Article
Publication Date
12-1-1997
Description
Intravenous injection of SP increases blood pressure, heart rate and renal nerve activity by stimulating sympathetic ganglia. This effect is greater in SHR than in WKY rats. The present study compared ganglion and cardiovascular responses to the native tachykinin SP and the NK, agonist GR73637 (GR) to determine the receptor type and the response profile in SHR and WKY rats. Anesthetized rats were treated with a ganglion blocker, chlorisondamine (25 μmol/kg), to prevent baroreceptor modulation of ganglion responses to SP and GR. GR (0.1 - 100 nmol/kg) caused dose-dependent effects in the two strains similar to those caused by SP. Maximum responses to SP and GR were: 1 renal nerve firing 1 blood pressure 1 heart rate strain n (mV2/sec) (mmHg) (beats/min) SP GR, SP GR SP GR SHR 8 151±23.9 122±18.0 32±4.2 19±2.6a 82± 9.6 62±7.2a WKY 6 36±11.4b 12± 3.1a,b 4±1.7b 0a,b 56±14.1b 16±4a,b mean±SEM; aGR different from SP; bWKY different from SHR These findings demonstrate that 1) GR has effects on blood pressure, heart rate and renal nerve firing similar to those caused by SP, 2) the magnitude of the responses to GR and SP is less in WKY rats than in SHR and 3) NK1 receptors have a major but not exclusive role in mediating renal nerve and cardiovascular responses to the ganglion action of the native tachykinin SP.
Citation Information
Hancock, J. C.; Tompkins, J. D.; and Hoover, D. B.. 1997. A Selective NK1 Tachykinin Receptor Agonist and Substance P (SP) Have Similar Effects on Sympathetic Ganglia, Blood Pressure and Heart Rate of Normotensive and Hypertensive Rats. FASEB Journal. Vol.11(3). ISSN: 0892-6638