Effect of postischemic hypoperfusion on vasodilatory mechanisms in cats

N. Clavier, Jeffrey Kirsch, P. D. Hurn, R. J. Traystman

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

We addressed the mechanism for reduced pial vascular reactivity to muscarinic stimulation by evaluating pial vessel responses to receptor- dependent [10-5 M acetylcholine (ACh)] and independent (10-5 M A-23187) agonists and the endothelium-independent nitric oxide (NO) donor [10-5 M nitroprusside (NP)]. Cerebral blood flow (CBF, microspheres) and pial arteriolar diameters (intravital microscopy) were measured in halothane- anesthetized cats. Cats (n = 13) were treated with 12 min of near-complete global cerebral ischemia, whereas control animals (n = 9) were identically instrumented but were not submitted to ischemia. Postischemic hypoperfusion was evident in most animals at 60 min of reperfusion, accompanied by attenuated pial arterial dilation to topical ACh (baseline dilation 23 ± 4% vs. postischemia 11 ± 3%) and A-23187 (16 ± 4 vs. 0 ± 3% dilation). Dilation to NP was unaffected. CBF response to intravenous administration of the muscarinic receptor agonist oxotremorine was also decreased throughout the forebrain (162 ± 12 vs. 116 ± 6% increase in flow) in these cats. These data suggest that endothelium-dependent vasodilation with topical muscarinic agonists is impaired during hypoperfusion, but vascular smooth muscle responsivity to NO remains intact. We conclude that the defect in the signal transduction pathway is not limited to the receptor and may involve an abnormality with NO synthesis or its destruction within endothelium.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume267
Issue number5 36-5
StatePublished - 1994
Externally publishedYes

Fingerprint

endothelium
agonists
nitric oxide
Dilatation
Cats
acetylcholine
cats
ischemia
Endothelium
blood vessels
Muscarinic Agonists
receptors
Calcimycin
Nitroprusside
Acetylcholine
Cerebrovascular Circulation
Nitric Oxide
vasodilation
halothane
Oxotremorine

Keywords

  • acetylcholine
  • calcium ionophore A-23817
  • cerebral blood flow
  • cerebral ischemia
  • pial vessels, nitric oxide

ASJC Scopus subject areas

  • Physiology
  • Agricultural and Biological Sciences(all)

Cite this

Effect of postischemic hypoperfusion on vasodilatory mechanisms in cats. / Clavier, N.; Kirsch, Jeffrey; Hurn, P. D.; Traystman, R. J.

In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 267, No. 5 36-5, 1994.

Research output: Contribution to journalArticle

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