Regulation of gastric acid secretion in situ by an endogenous activator protein: Studies with activator-specific antibody

Monospecific polyclonal antibody was raised against a homogenous preparation of endogenous activator protein (HAF) for the gastric H+,K+-ATPase system. Antibody was used to assess the regulatory role of the HAF in gastric acid secretion by isolated rabbit glands in situ. Immunohistochemical studies revealed aredistribution of theHAFtowards discrete intracellular zones following stimulation of the glands with histamine. The antibody, when inserted into the stimulated gastric glands by digitonin permeabilization, could effectively block the acid forming ability of the cells. The data offers, for the first time, some concrete in situ evidence for the role of the HAF as an intracellular regulator of gastric H+ transport .The manuscript was written (in the early 1990) soon after the data were collected, but never submitted to a journal with the hope of getting better gel picture and fluorescent micrograph which did not materialize due to unavoidable circumstances

Antiulcerogenic Effects and Possible Mechanism of Action of Quassia Amara (L. Simaroubaceae) Extract and Its Bioactive Principles in Rats

The effects of Quassia amara extract (Q. amara) and its bioactive principles-quassin and 2-methoxycanthin-6-one on gastric ulceration were studied in albino rats. Q. amara (200-800 mg/kg p.o.; 5-20 mg/kg i.p) and 2-methoxycanthin-6-one (12.5, 25.0 and 50.0 mg/kg p.o; 1, 2 and 4 mg/kg i.p) but not quassin (12.5, 25.0 and 50 mg/kg p.o; 1, 2 and 4 mg/kg i.p) significantly inhibited gastric ulceration induced by indomethacin (40mg/kg). Administration of Q. amara (800 mg/kg p.o and 20 mg/kg i.p) and 2-methoxycanthin-6-one (12.5 mg/kg p.o; 4 mg/kg i.p) caused between 77%-85% cytoprotection against indomethacin (40 mg/kg, i.p) – induced gastric ulceration. Quassin did not cause any significant change in indomethacin-induced gastric ulceration. The inhibition of gastric ulceration produced by Q. amara and 2-methoxycanthin-6 one was accompanied by significant dosedependentdecreases (P< 0.01) in total gastric acidity. To investigate the probable mechanism of action, the individual effects of the extract and its principles alone and in combination with histamine (1 mg/kg) or cimetidine (0.12 mg/kg) on gastric acid secretion in situ were studied. Q. amara (20 mg/kg) and 2-methoxycanthin-6-one (4 mg/kg) but not quassin significantly (P< 0.01) inhibited the basal and histamine-induced gastric acid secretion. Inhibition of gastric acid secretion by Q. amara and 2-methoxycanthin-6-one was accentuated by cimetidine. The results suggest that Q. amara and its bioactive principle, 2- methoxycanthin-6-one possess antiulcer activity probably acting via histamine H2 receptor. This could be a potential source of potent and effective antiulcer agents.Keywords: Quassia amara; gastric ulceration; gastric acid; quassin; 2-methoxycanthin-6-one; ra

Regulation of CA II and H + , K + -ATPase Gene Expression in Canine Gastric Parietal Cells

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75197/1/j.1749-6632.1989.tb25154.x.pd