Acta Physiologica 77. (1991)

3-4. szám - G. A. Bálint: Prostacyclin-induced activation of 2'-5'-cyclic adenosine monophosphate-dependent protein kinase in rat antral and fundic gastric mucosa

Acta Physiologica Hungarica, Volume 77 (3—4), jop. 191—195 (1991) PROSTACYCLIN-INDUCED ACTIVATION OF 3’-5’-CYCLIC ADENOSINE MONOPHOSPHATE-DEPENDENT PROTEIN KINASE IN RAT ANTRAL AND FUNDIC GASTRIC MUCOSA G. A. BÁLINT DEPARTMENT OF PHARMACOLOGY, (S. P.); ADDIS ABABA UNIVERSITY, ADDIS ABABA, ETHIOPIA Received September 28, 1990 Accepted October 24, 1990 The present investigations showed that after oral prostacyclin administration (100 pg/kg) as soon as the intracellular level of cAMP is elevated the activation of cAMP-dependent protein kinase follows in both parts (antrum and fundus) of rat gastric mucosa. The enzyme activation seems to be more significant in the fundic region which is in a complete agreement with the previously published results, i.e. the fundic mucosa reacts with de novo protein synthesis toward noxious agents (resulting finally in new cell formation), while the antral mucosa is more durable against damaging noxae. Taking into consideration all available data in the literature it seems that the intracellular effect of the exogenously administered prostacyclin in the gastric mucosa is a polyphasic effect, which contains the following consecutive steps: 1. Binding to the cell surface; 2. Effect on the intracellular second messenger system, (cAMP, cGMP); 3. Activation of the calmodulin system; 4. cAMP-dependent protein kinase activation; 5. DNA, RNA changes; 6. Influence on protein synthesis, and finally; 7. New cell formation. Keywords: Prostacyclin, gastric mucosa, cAMP, cGMP, protein kinase. List of Abbreviations Used: cAMP: 3’-5’-cyclic Adenosine Monophosphate; cAMPd-PK: cAMP-dependent Protein Kinase; ATP: Adenosine-triphosphate; DNA: Deoxyribonucleic acid; EDTA: Ethylene-diamine-tetraacetic acid; cGMP: 3’-5’-cyclic Guanosine Monophos­phate; PG-I2: Prostacyclin; RNA: Ribonucleic acid; TCA: Trichloracetic acid; Tris (HCl): 2-amino-2-(hydroxymethyl)-l,3-propanediol (hydrochloride). According to Bálint and his co-workers the exogenously administered PG-I2 exerts a polyphasic effect on rat gastric mucosa, i.e. after a quick “hit and run” effect it starts a series of consecutive reactions and although the drug itself becomes quickly inactive the process continues, resulting finally in new cell formation [1, 3, 4]. Present (permanent) address and all correspondence should be sent to: Dept, of Neurology and Psychiatry, (Clin. Pharmacol. Lab.), Albert Szent-Györgyi Medical University, H-6701 Szeged, P.O. Box 397. Hungary Acta Physiologica Hur.garica 77, 1991 Akadémiai Kiadó, Budapest

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