Persistence of central respiratory rhythmogenesis after maximal acetylcholinesterase inhibition in unanaesthetized cats.
Cats were given systemically the anticholinesterase paraoxon at a dosage (3 mg/kg i.v.) that produced a maximal (over 90%) inhibition of brainstem acetylcholinesterase. All paralyzed and artificially ventilated animals were either unanaesthetized (decerebrated or ventilated with 70% nitrous oxide and 30% oxygen) or anaesthetized (with pentobarbital, alpha-chloralose, or halothane). In unanaesthetized cats, paraoxon produced an immediate rise in arterial blood pressure and did not suppress phrenic nerve respiratory discharges, while in anaesthetized animals it produced an immediate and long-lasting hypotension and a complete arrest of central respiratory activity. It is concluded that acetylcholine accumulation may not suppress respiratory rhythmogenesis and that most anaesthetics may considerably alter the response of cardiorespiratory cholinergic mechanisms to anticholinesterase administration.
Foutz
A S
AS
Laboratoire de physiologie nerveuse, Centre national de la recherche scientifique, Gif-sur-Yvette, France.
Delamanche
I S
IS
Denavit-Saubié
M
M
D000110:Acetylcholinesterase / Q000378:metabolism*; D000758:Anesthesia; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002415:Cats; D002698:Chloralose; D002800:Cholinesterase Inhibitors / Q000494:pharmacology*; D003655:Decerebrate State; D004569:Electroencephalography; D005260:Female; D006221:Halothane; D008297:Male; D009609:Nitrous Oxide; D010261:Paraoxon / Q000494:pharmacology; D010424:Pentobarbital; D010791:Phrenic Nerve / Q000187:drug effects; D012132:Respiratory Muscles / Q000187:drug effects*
D002800:Cholinesterase Inhibitors; D002698:Chloralose; D000110:Acetylcholinesterase; D010424:Pentobarbital; D009609:Nitrous Oxide; D010261:Paraoxon; D006221:Halothane