| RESEARCH PAPER
|Year : 1998 | Volume
| Issue : 3 | Page : 186-190
The relation between centrally situated noradrenergic, adenosine-A, and GABA, receptors while inhibiting gastric acid secretion in pylorus ligated conscious rats
PR Thakur, SN Umathe
Objectives: To evaluate the relationship between centrally situated noradrenergic, adenosine-A, and GABAB receptors particularly because activation of each of them is known to inhibit gastric acid secretion.
Methods: The total gastric acid output over a period of 4 h was investigated in pylorus ligated conscious rats who had received following i.c.v. treatments through a chronically implanted screw cannula in skull. In the first set of experiments rats were treated with an agonist i.e. either noradrenaline (NA,1 'g/rat) or balcofen (5'g/rat) or (-) N6 phenyl isopropyladenosine (L-PIA,10 'g/rat) just after the pylorus ligation. In the second set of experiments the rats received either prazosin ((-adrenergic blocker, 5 'g/rat) or 8 phenyltheophylline (8-PT, adenosine A, antagonist, 50'g/rat) or phaclofen (GABAB antagonist, 5 'g/ rat) 20 minutes prior to the administration of either NA (1 'g/rat) or baclofen (5 'g/rat) or L-PIA (10 'g/rat).
Results : The i.c.v. administration of NA, L-PIA and baclofen significantly inhibited gastric acid output in pylorus ligated conscious rats. Prior treatment of rats with prazosin attenuated the antisecretory effect of NA as well as L-PIA, whereas the effect of baclofen remained unaffected. 8-PT and phaclofen, however, could only attenuate the antisecretory effect of L-PIA and baclofen respectively.
Conclusion: The centrally situated adenosine-A, receptors operate through (-adrenergic receptors while inhibiting gastric acid secretion. The activation of centrally situated phaclofen sensitive GABAB receptors independently inhibit acid secretion and does not bear any relation with centrally situated (-adrenergic or adenosine-A, receptors.
P R Thakur
Source of Support: None, Conflict of Interest: None