Substance K: Vascular and cardiac effects in rat and pig

J. Eimerl, M. A. Bayorh, Z. Zukowska-Grojec, A. I. Faden, D. Ezra, G. Feuerstein*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The effects of substance K (SK), a newly discovered tachykinin, on the cardiovascular and sympathetic system were evaluated in the pithed rat preparation and in the in situ domestic pig heart. In pithed rats, SK (10 nmol/kg, IV) produced a triphasic mean blood pressure (MAP) response: short depressor, short pressor (+11±1 mmHg), and prolonged depressor phase (-9±1 mmHg, n=9-24, p<0.001). Neither effect was significantly affected by pretreatment with propranolol (2 mg/kg) or phentolamine (1 mg/kg). The pressor response was accompanied by increased heart rate (HR): 41±4 beats/min, while lower doses produced a decrease: -8±2 beats/min (p<0.01). Propranolol abolished the increase in HR. SK inhibited the pressor response evoked by electrical stimulation of the spinal cord (SCS) and by Arg8-vasopressin (AVP). SK increased circulating levels of epinephrine and norepinephrine but did not change release of catecholamines evoked by SCS. Direct intracoronary injections of SK (0.3-100 nmol, intact pig heart) increased coronary blood flow; higher doses decreased MAP and increased HR. These results indicate that: (1) SK can produce pressor and depressor effects in the rat and is a potent coronary dilator in the pig. (2) In the pithed rat SK causes catecholamine release which mediates its cardiac accelerator effect and it antagonizes adrenergic and non-adrenergic pressor stimuli.

Original languageEnglish
Pages (from-to)149-153
Number of pages5
JournalPeptides
Volume6
Issue numberSUPPL. 2
DOIs
StatePublished - 1985
Externally publishedYes

Keywords

  • Blood pressure
  • Catecholamines
  • Coronary blood flow
  • Heart rate
  • Neuromedins
  • Pithed rat
  • Substance K
  • Tachykinins

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