Author/Editor     Stanovnik, Lovro
Title     Determining the parameters of concentration-response relationship for histamine on the isolated portion of guinea pig stomach and guinea pig right atrium
Type     članek
Source     Pflugers Arch
Vol. and No.     Letnik 440, št. 5 Suppl
Publication year     2000
Volume     str. R197-9
Language     eng
Abstract     In our previous experiments measuring acid secretion in the isolated mouse stomach we found higher EC50 values (agonist concentiation evoking half maximal effect for histamine than in the experiments on the isolated guinea pig right atrium (contraction frequency). The difference could be due to nonequilibrium conditions in the isolated mouse stomach preparation or to species differences. In order to check this possibility and to test the consistency of concentration-response relationship (CRR) parameter determination on an isolated secretory organ, we compared EC50 for histamine and pA2 for famotidine on the two isolated preparations from the same species, guinea pigs. Both, EC50 and pA2 values were significantly different when measuring gastric acid secretion (9.7 micro M and 6.07) from the parameters, found in the isolated right atrium measuring frequency of contractions (1.6 micro M and 7.06). From these results it can be concluded that the isolated portion of guinea pig stomach is suitable for CRR determination; but the parameters obtained are in the range of higher concentrations than the heal ones because of kinetic particularities of the preparation.
Descriptors     HISTAMINE
GASTRIC ACID
HEART ATRIUM
HEART RATE
FAMOTIDINE
GUINEA PIGS