title: Hypertonic saline reverses bupivacaine-induced depression of rabbit Purkinje fiber depolarization Vmax.
abstract: The present study describes the effect of a hypertonic increase in sodium chloride concentration on electrophysiological parameters. Membrane depolarization was recorded from rabbit Purkinje fibers superfused with warm, aerated Tyrode solution. An amount of 5% NaCl above that in normal Tyrode solution (HyNaCl, 344 mOsm) was added to the bathing medium for 30 min, significantly increasing the maximal rate of depolarization (Vmax +15% vs -7% for control), with minor effects on other parameters. When bupivacaine was superfused over the preparation for 30 min either in normal Tyrode or in HyNaCl, Vmax was significantly decreased (33% and 15%, respectively). HyNaCl protected the cardiac tissues from the depressive effect of 0.5 microgram/ml bupivacaine. We suggest that the infusion of hypertonic saline in intact animals may prove effective in preventing or reversing the cardiodepressant effect of bupivacaine.
authors.affiliation: Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115.
authors.forename: M P
authors.initials: MP
authors.lastname: Simonetti
authors.forename: R A
authors.initials: RA
authors.lastname: Moller
authors.forename: B G
authors.initials: BG
authors.lastname: Covino
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002045:Bupivacaine / Q000037:antagonists & inhibitors*; D003864:Depression, Chemical; D006329:Heart Conduction System / Q000187:drug effects*; D006982:Hypertonic Solutions / Q000494:pharmacology*; D007552:Isotonic Solutions / Q000494:pharmacology*; D008297:Male; D011690:Purkinje Fibers / Q000187:drug effects*; D011817:Rabbits
chemical_list: D006982:Hypertonic Solutions; D007552:Isotonic Solutions; C037692:Tyrode's solution; D002045:Bupivacaine