Electrically stimulated Krebs-Henseleit buffer does not relax precontracted human bronchi in vitro.
Electric field stimulation (EFS) causes a non-adrenergic relaxation of precontracted human airways. Only 10-20% of this response can be blocked with the nervous conductance blocker tetrodotoxin (TTX). Therefore, 80-90% of the non-adrenergic relaxation is not neurally mediated. The mechanism of this non-neural component is unclear. We examined whether EFS induces the generation of muscle relaxing substances in oxygenated Krebs-Henseleit buffer. Strips of central airways of 6 patients were precontracted with methacholine (10(-5) M) and exposed to Krebs buffer that had previously been stimulated with EFS (50 V, 0.3 ms, 30 s, 1-50 Hz). Results were compared to those obtained with unstimulated buffer. The contractile state of the airways did not change significantly with either EFS-stimulated or unstimulated buffer. We conclude that in oxygenated Krebs buffer EFS does not cause generation of substances that change the contractile state of prestimulated human airways.
Jongejan
R C
RC
Department of Paediatric Respiratory Diseases, Erasmus University, Rotterdam, The Netherlands.
de Jongste
J C
JC
Raatgeep
R C
RC
Bonta
I L
IL
Kerrebijn
K F
KF
D001980:Bronchi / Q000187:drug effects*; D002021:Buffers; D004558:Electric Stimulation; D006801:Humans; D066298:In Vitro Techniques; D008688:Methacholine Compounds / Q000494:pharmacology; D009126:Muscle Relaxation / Q000187:drug effects
D002021:Buffers; D008688:Methacholine Compounds