PT  - JOURNAL ARTICLE
AU  - Harold F. Hardman
AU  - Joanne I. Moore
AU  - Bert K. B. Lum
TI  - A METHOD FOR ANALYZING THE EFFECT OF pH AND THE IONIZATION OF DRUGS UPON CARDIAC TISSUE WITH SPECIAL REFERENCE TO PENTOBARBITAL
DP  - 1959 Jun 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 136--142
VI  - 126
IP  - 2
4099  - http://jpet.aspetjournals.org/content/126/2/136.short
4100  - http://jpet.aspetjournals.org/content/126/2/136.full
SO  - J Pharmacol Exp Ther1959 Jun 01; 126
AB  - A method employing the isolated perfused turtle heart as a test system for examining the effects of pH and drug ionization upon cardiac tissue over a wide pH range has been described. The degree of negative inotropic activity observed with sodium pentobarbital in the isolatedperfused turtle and rabbit heart is directly proportional to the concentration of unionized pentobarbital present in the perfusion medium. The ionized form of pentobarbital (anion) did not exhibit any negative inotropic activity inthe isolated perfused turtle and rabbit heart in any of the concentrations tested. The original hypothesis of Clowes et al. (1940) concerning the depressant action ofseveral barbiturates on arbacia eggs has been found applicable to the action of pentobarbital on turtle and rabbit cardiac tissue within a restricted pH range.