Rate of pressure change and hyperbaric bradycardia in the mouse sinus node.
Sinus node preparations from mice were hydraulically compressed at 10, 100, and 500 atm x min-1 in Tyrode's solution at 27 degrees C. At the highest compression rate, both a delay and a more pronounced beating frequency response to pressure was seen. The delayed reaction is ascribed to either adiabatic effects or a time-delay in conformational changes in the pacemaker cell membrane. The potentiating effect of a high compression rate could be eliminated by autonomic blockade (atropine and practolol).
D000818:Animals; D001145:Arrhythmias, Cardiac; D001285:Atropine / Q000494:pharmacology; D003664:Decompression; D005260:Female; D006325:Heart Atria / Q000187:drug effects / Q000503:physiopathology; D006339:Heart Rate; D006358:Hot Temperature; D006874:Hydrostatic Pressure / Q000009:adverse effects*; D051379:Mice; D011217:Practolol / Q000494:pharmacology; D011312:Pressure / Q000009:adverse effects*; D013997:Time Factors
D001285:Atropine; D011217:Practolol