Biomedical subjects

N Homma

Publications and source records attributed to N Homma.

At least 55 records · Page 3Linked to original sources

PubMed1986

Blocking effects of verapamil on pancreatic exocrine secretion induced by dopamine in the dog.

The effects of verapamil on the dopamine-induced pancreatic exocrine secretion were investigated in the isolated and blood-perfused canine pancreas at a constant flow rate in situ. All drugs were given intra-arterially. Dose-related increases in the volume of pancreatic secretion induced by dopamine (1-10 micrograms) were reduced by infusion of 50 and 100 micrograms/min of verapamil, but were not affected by diltiazem (100 micrograms/min) and dilazep (100 micrograms/min) infusions. Protein concentration in pancreatic juice induced by dopamine was decreased significantly by the infusion of verapamil, diltiazem and dilazep, but bicarbonate concentration was not. These results suggest that verapamil reduced the dopamine-induced pancreatic secretion by virtue of its dopamine antagonist activity and inhibited protein secretion by virtue of its calcium channel blocking action.

Animals↗

PubMed1985

Adenosine potentiates secretin-stimulated pancreatic exocrine secretion in the dog.

Pretreatment with graded doses of adenosine (0.1-1.0 mg), injected close-arterially (i.a.) to the vascularly isolated and self-hemoperfused dog pancreas, increased secretin (0.025 units i.a.)-stimulated secretory volume dose dependently and this effect of adenosine was reversed by further pretreatment with theophylline (0.3 mg i.a.). Adenosine itself did not affect the rate of resting secretion and the concentrations of protein and bicarbonate of the resting pancreatic juice. Adenosine decreased the concentration of protein and increased that of bicarbonate in the pancreatic juice stimulated by secretin. Adenosine, however, did not affect dopamine (3 micrograms i.a.)-stimulated pancreatic secretion. Adenosine (0.1-1.0 mg i.a.)-induced vasodilation was also reversed by the pretreatment with theophylline (0.3 mg i.a.). These results suggest the existence of adenosine 'R' receptors in the exocrine cells and the vasculature of the dog pancreas.

Adenosine↗

PubMed1985

Effects of synthesized phosphodiesterase inhibitors, DM 9278 and HWA 285, on pancreatic exocrine secretion of the dog.

The effects of synthesized phosphodiesterase inhibitors, DM 9278 and HWA 285, on pancreatic exocrine secretion were investigated in isolated and blood-perfused canine pancreas. Close-arterial injections of DM 9278 (10-300 micrograms) and HWA 285 (300-3000 micrograms) caused dose-dependent increases in the flow rate of pancreatic juice and perfusion blood flow. Bicarbonate concentration in the pancreatic juice stimulated by DM 9278 (300 micrograms) or HWA 285 (3000 micrograms) was significantly higher than that in the resting pancreatic juice, although neither of the compounds affected protein concentrations in the pancreatic juice. In the secretory volume, 100 micrograms of DM 9278 corresponded roughly to 1000 micrograms of HWA 285, 0.1 units of secretin or 0.3 units of pancreozymin. These secretory and vascular effects were not modified by pretreatment with atropine or sulpiride. This study suggests that both DM 9278 and HWA 285 act directly on ductular cells of the pancreas and induce secretion of water and electrolytes.

Animals↗

PubMed1985

Effects of isosorbide dinitrate on pancreatic exocrine secretion in the dog.

The effects of isosorbide dinitrate (ISDN) on pancreatic exocrine secretion were investigated after intravenous administration in the whole animal and after close-arterial administration on the isolated and blood-perfused dog pancreas preparations. ISDN (10-100 micrograms/kg), injected into the femoral vein, caused a dose-dependent increase in flow rate of pancreatic juice and in protein concentration of the pancreatic juice. Close-arterial injections of ISDN (100-1000 micrograms) produced a dose-dependent increase in perfusion blood flow, flow rate of pancreatic juice and protein concentration of the pancreatic juice without affecting its bicarbonate concentration. These vascular and secretory effects were not modified by pretreatment with atropine. From these data, it is suggested that ISDN induces pancreatic enzyme secretion by acting directly on the acinar cells of the pancreas.

Animals↗

PubMed1984