Effect of hypoxia on the contractile response to KCl, prostaglandin F2 alpha, and hemoglobin

Tadayoshi Nakagomi; Neal F Kassell; Tomio Sasaki; Shigeru Fujiwara; R Michael Lehman; Hiroo Johshita; James C Torner

doi:10.3171/jns.1987.67.4.0565

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Effect of hypoxia on the contractile response to KCl, prostaglandin F2 alpha, and hemoglobin

Journal article

Peer reviewed

Effect of hypoxia on the contractile response to KCl, prostaglandin F2 alpha, and hemoglobin

Tadayoshi Nakagomi, Neal F Kassell, Tomio Sasaki, Shigeru Fujiwara, R Michael Lehman, Hiroo Johshita and James C Torner

Journal of neurosurgery, Vol.67(4), pp.565-572

10/1987

DOI: 10.3171/jns.1987.67.4.0565

PMID: 3477614

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Abstract

The purpose of this experiment was to evaluate the effect of hypoxia on the in vitro contractile responses of canine basilar artery to KCl, prostaglandin (PG) F2 alpha, and hemoglobin. Hypoxia was induced by changing the bubbling gas mixture in the chamber from 95% O2/5% CO2 to 95% N2/5% CO2. Hypoxia augmented the contractile response developed at 95% O2 to 25 mM and 50 mM KCl, 3 X 10(-7) M and 10(-5) M PGF2 alpha, and 10(-6) M hemoglobin. No significant alteration of the hypoxic augmentation in any preparation exposed to 25 mM KCl, 3 X 10(-7) M PGF2 alpha, or 10(-6) M hemoglobin was observed with guanethidine (10(-5) M), prazosin (10(-5) M), methysergide (10(-5) M), or diphenhydramine (10(-5) M). Endothelial denudation did not affect hypoxic augmentation. Hypoxia did not cause any alteration of the contractile response to 10(-6) M PGF2 alpha in Ca++-free media. Pretreatment with a calcium channel blocker, nicardipine, significantly inhibited the hypoxic potentiation of the contractile response to 25 mM KCl, 3 X 10(-7) M PGF2 alpha, and 10(-6) M hemoglobin. These results suggest that hypoxia augments the contractile response to these agonists by a direct action on the smooth-muscle cells, facilitating the transmembrane influx of extracellular calcium. Hypoxia of smooth-muscle cells in the major cerebral arteries might be involved in the pathogenesis of vasospasm.

Basilar Artery - drug effects

Dinoprost

Male

Endothelium, Vascular - physiology

Hypoxia, Brain - physiopathology

Animals

Calcium - physiology

Muscle Contraction - drug effects

Potassium Chloride - pharmacology

Dogs

Hemoglobins - physiology

Prostaglandins F - pharmacology

Female

Basilar Artery - physiology

Nicardipine - pharmacology

In Vitro Techniques

Muscle, Smooth, Vascular - physiology

Muscle, Smooth, Vascular - drug effects

Details

Title: Subtitle: Effect of hypoxia on the contractile response to KCl, prostaglandin F2 alpha, and hemoglobin
Creators: Tadayoshi Nakagomi - Department of Neurological Surgery, University of Virginia School of Medicine, Charlottesville
Neal F Kassell
Tomio Sasaki
Shigeru Fujiwara
R Michael Lehman
Hiroo Johshita
James C Torner
Resource Type: Journal article
Publication Details: Journal of neurosurgery, Vol.67(4), pp.565-572
DOI: 10.3171/jns.1987.67.4.0565
PMID: 3477614
NLM abbreviation: J Neurosurg
ISSN: 0022-3085
eISSN: 1933-0693
Publisher: United States
Language: English
Date published: 10/1987
Academic Unit: Epidemiology; Surgery; Injury Prevention Research Center; Neurosurgery
Record Identifier: 9983995111702771

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