Acetazolamide and respiratory chemosensitivity to CO(2) in the neonatal rat transverse medullary slice.
Hypoglossal nerve rootlets in the transverse medullary slice prepared from neonatal rats exhibit a bursting 'respiratory' rhythm that increases in frequency with CO(2), presumably due to activation of chemosensitive cells such as the central chemoreceptors. Carbonic anhydrase is associated with areas of central chemoreception and we propose a hypothesis for its involvement in the chemoreception process. We tested this hypothesis by blocking its activity with acetazolamide in six slice preparations. However, the addition of 1 mM acetazolamide dissolved in dimethyl sulphoxide to the superfusing bathing solution produced no alteration in the bursting frequency response of the slice to CO(2). We concluded that the chemoreception process producing the CO(2) response of the superfused, transverse medullary slice does not involve carbonic anhydrase.
Department of Physiology, University of Toronto, Toronto, Ont, Canada M5S 1A8.
Aleksandar
A
Necakov
John H
JH
Peever
Linlin
L
Shen
James
J
Duffin
D000086:Acetazolamide / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D001933:Brain Stem / Q000187:drug effects / Q000502:physiology*; D002245:Carbon Dioxide / Q000494:pharmacology*; D002257:Carbonic Anhydrase Inhibitors / Q000494:pharmacology*; D002628:Chemoreceptor Cells / Q000187:drug effects / Q000502:physiology; D004594:Electrophysiology / Q000379:methods; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007002:Hypoglossal Nerve / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley; D012119:Respiration / Q000187:drug effects*
D002257:Carbonic Anhydrase Inhibitors; D002245:Carbon Dioxide; D000086:Acetazolamide