Acid secretion by isolated canine gastric mucosa.

Abstract

SUMMARY1. An isolated gastric mucosal preparation from the dog stomach which is capable of acid secretion is described. Average values for normal resting potential difference (p.d.) was 49 + 2 mV (mucosal side negative with respect to the serosal side), shortcircuit current (I8c) was 172 + 4 ,uA and resistance (R) was 285 + 6 Q. cm2. Low rates of spontaneous acid secretion (0-0.58,uequiv/cm2.hr) were present initially but following short-circuiting of the tissue these values decreased to low levels (less than 0.1 uequiv/cm2. hr) within an hour.2. Histamine in doses exceeding 10-6 M stimulated acid secretion, increased Ih, and decreased R. Concentrations ranging from 10-5 to 8 x 10-4 M produced maximal secretion. The maximal secretary rate achieved was 4-24 + 0 35 ,uequiv/cm2. hr.3. Pentagastrin (10-8 M) and acetylcholine (10-6-10-5 M) also stimulated acid secretion with a lower maximal secretion as compared to histamine stimulation. These concentrations of pentagastrin and acetylcholine did not alter histamine stimulated acid secretion. Higher concentrations of pentagastrin (10-6 M) and acetylcholine (10-4 M) reversibly inhibited acid secretion of histamine stimulated mucosa.4. These results demonstrate that there are many similarities between in vitro and in vivo findings on the dog stomach, indicating the great potential of the in vitro dog gastric mucosa for studies on the mechanism of action and interaction of gastric secretagogues.

Chloride, sodium, potassium and hydrogen ion transport in isolated canine gastric mucosa.

“…6-25 ± 0-38 (7) 4-30 ± 0-06 (7)* R (Q.cm2) 264±11 (7) 354±17 ( addition (Table 3) confirm previous studies (Kuo & Shanbour, 1978). Histamine produced an initial increase then a decrease in I'c and a decrease in R. In separate experiments, 10--M-pentagastrin and 2 x 10-6 M-acetylcholine were added into the serosal solution following the resting stage.…”

“…Unidirectional fluxes of C1-and Na+ from serosal to mucosal side and from mucosal to serosal side and net fluxes are shown in & Shanbour, 1978). The corresponding electrophysiological properties of the tissues are presented in Table 3.…”

“…The net flux of Na+ was not significantly different between the resting and secreting stages. Since it has been found that higher concentrations of pentagastrin (10-6 M) or acetylcholine (10-4 M) inhibit histamine stimulated gastric acid secretion (Kuo & Shanbour, 1978), the effects of these concentrations of pentagastrin and acetylcholine on Na+ and Cl-fluxes following histamine stimulation were also investigated. Pentagastrin (10-6 M) and acetylcholine IC (/uequiv/Cm2.hr)…”

“…histamine, pentagastrin and acetylcholine (Kuo & Shanbour, 1978). Although Na+ and Cl-transport across in vitro dog stomach has been studied by Kitahara, Fox & Hogben (1969), essentially no information is available on the inter-relationships of these flux data with gastric H+ secretion, since their preparations were limited to the non-secreting state.…”

“…The relative contributions of H+, Cl-, Na+ and K+ transport to the electrophysiological activity of the tissue were also evaluated. METHODS Gastric mucosae from dogs were prepared in the manner described in previous publications (Kuo, Shanbour & Sernka, 1974;Kuo & Shanbour, 1978). Briefly, fasted (48 hr) mongrel dogs of either sex (10-20 kg) were anaesthetized with chloralose and ethyl carbamate (1 ml./kg of a solution containing 9-25 g chloralose and 92-5 g ethyl carbamate in 150 ml.…”