Adenosine: differential effect on blood flow to subregions of the upper gastrointestinal tract.
The potential of adenosine to regulate organ blood flow (ml/min/100 g tissue) in the intact rabbit upper alimentary tract was evaluated using the radioactive microsphere technique. Adenosine (1.0 mumole/kg/min) produced significant, greater than threefold increases in esophageal mucosal blood flow (37 +/- 2 to 127 +/- 47) and threefold increases in antral mucosal (39 +/- 3 to 144 +/- 24) and transmural small intestinal blood flow (duodenum, 60 +/- 13 to 187 +/- 22; jejunum, 42 +/- 3 to 138 +/- 16; ileum, 27 +/- 2 to 80 +/- 22). Inosine did not reproduce these effects. P1-purinergic receptor antagonism with theophylline blocked the effects of adenosine. 5'-(N-Ethylcarboxamido)adenosine, an agonist of A2-subtype, P1-purinergic receptors, increased gastrointestinal organ blood flow similarly to adenosine with nmole/kg/min doses. Similar doses of the A1-subtype agonist, N5-cyclohexyladenosine, were ineffective, but mumole/kg/min doses produced small effects on esophageal mucosa and ileum. Our results indicate that in rabbit alimentary organs, adenosine preferentially increases blood flow to esophageal mucosa, antral mucosa, and small intestine. Its effects are mediated by the A2-subtype of P1-purinergic receptors.
Pennanen
M F
MF
Department of Surgery, Department of Veterans Affairs Medical Center, Georgetown University, Washington, DC.
Bass
B L
BL
Dziki
A J
AJ
Harmon
J W
JW
D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology*; D019830:Adenosine-5'-(N-ethylcarboxamide); D000818:Animals; D004386:Duodenum / Q000098:blood supply; D004947:Esophagus / Q000098:blood supply*; D005748:Gastric Fundus / Q000098:blood supply; D005753:Gastric Mucosa / Q000098:blood supply*; D007082:Ileum / Q000098:blood supply; D007288:Inosine / Q000494:pharmacology; D007421:Intestine, Small / Q000098:blood supply*; D007583:Jejunum / Q000098:blood supply; D009092:Mucous Membrane / Q000098:blood supply; D009130:Muscle, Smooth / Q000098:blood supply; D009928:Organ Specificity; D058915:Purinergic P1 Receptor Antagonists; D011706:Pyloric Antrum / Q000098:blood supply*; D011817:Rabbits; D018047:Receptors, Purinergic P1 / Q000502:physiology; D012039:Regional Blood Flow / Q000187:drug effects*; D013806:Theophylline / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
D058915:Purinergic P1 Receptor Antagonists; D018047:Receptors, Purinergic P1; D014665:Vasodilator Agents; D019830:Adenosine-5'-(N-ethylcarboxamide); C027513:N(6)-cyclohexyladenosine; D007288:Inosine; D013806:Theophylline; D000241:Adenosine