TY - JOUR
T1 - Effects of histamine and histamine receptor antagonists on ion transport in rabbit descending colon
AU - McCabe, R. D.
AU - Smith, P. L.
PY - 1984
Y1 - 1984
N2 - The effects of histamine on colonic ion transport were examined in in vitro preparations of rabbit descending colon. Serosal addition of histamine (10-5 M) produced a transient increase in short-circuit current [I(sc)] and transepithelial conductance. The I(sc) response to histamine could be blocked by removing Cl from both bathing solutions, adding furosemide (10-3 M) to the serosal bathing solution, adding indomethacin to the serosal and mucosal bathing solutions (10-5 M), or removing Ca from the serosal bathing solution. In addition, the histamine-induced increase in I(sc) was inhibited in a dose-dependent manner by the H1-receptor antagonist diphenhydramine, with a maximal inhibition at 10-4 M and a half-maximal inhibition at 3 x 10-7 M. The H2-receptor antagonist cimetidine (10-3 M) was without effect on the histamine response. Measurement of unidirectional Na, K, and Cl fluxes revealed that serosal addition of diphenhydramine (10-3 M) reduced basal I(sc) due to a decrease in mucosal-to-serosal Na flux. Serosal addition of diphenhydramine (10-3 M) also inhibited the increase in I(sc) produced by serosal addition of prostaglandin E1, 8-bromo-cAMP, cholera toxin, or the ionophore A23187. Measurement of unidirectional K and Cl fluxes revealed that prostaglandin E1 alone increased serosal-to-mucosal K and Cl fluxes and reduced the mucosal-to-serosal K flux, thereby increasing net K and Cl secretion. Serosal diphenhydramine (10-3 M) abolished the changes in Cl fluxes produced by prostaglandin E1 and reduced the magnitude of the changes in K fluxes. This study suggests that ion transport by rabbit descending colon is altered by histamine via H1-receptors.
AB - The effects of histamine on colonic ion transport were examined in in vitro preparations of rabbit descending colon. Serosal addition of histamine (10-5 M) produced a transient increase in short-circuit current [I(sc)] and transepithelial conductance. The I(sc) response to histamine could be blocked by removing Cl from both bathing solutions, adding furosemide (10-3 M) to the serosal bathing solution, adding indomethacin to the serosal and mucosal bathing solutions (10-5 M), or removing Ca from the serosal bathing solution. In addition, the histamine-induced increase in I(sc) was inhibited in a dose-dependent manner by the H1-receptor antagonist diphenhydramine, with a maximal inhibition at 10-4 M and a half-maximal inhibition at 3 x 10-7 M. The H2-receptor antagonist cimetidine (10-3 M) was without effect on the histamine response. Measurement of unidirectional Na, K, and Cl fluxes revealed that serosal addition of diphenhydramine (10-3 M) reduced basal I(sc) due to a decrease in mucosal-to-serosal Na flux. Serosal addition of diphenhydramine (10-3 M) also inhibited the increase in I(sc) produced by serosal addition of prostaglandin E1, 8-bromo-cAMP, cholera toxin, or the ionophore A23187. Measurement of unidirectional K and Cl fluxes revealed that prostaglandin E1 alone increased serosal-to-mucosal K and Cl fluxes and reduced the mucosal-to-serosal K flux, thereby increasing net K and Cl secretion. Serosal diphenhydramine (10-3 M) abolished the changes in Cl fluxes produced by prostaglandin E1 and reduced the magnitude of the changes in K fluxes. This study suggests that ion transport by rabbit descending colon is altered by histamine via H1-receptors.
UR - http://www.scopus.com/inward/record.url?scp=0021503255&partnerID=8YFLogxK
U2 - 10.1152/ajpgi.1984.247.4.g411
DO - 10.1152/ajpgi.1984.247.4.g411
M3 - Article
C2 - 6149689
AN - SCOPUS:0021503255
VL - 10
SP - G411-G418
JO - American Journal of Physiology - Gastrointestinal and Liver Physiology
JF - American Journal of Physiology - Gastrointestinal and Liver Physiology
SN - 0193-1857
IS - 4
ER -