Hypoxia increases the cyclic AMP content of the cat carotid body in vitro.

Abstract

The cyclic AMP content of cat carotid bodies in vitro measured with a radioimmunoassay under control conditions (PO2: 230 torr) was 0.79 +/- 0.10 pmol/carotid body (n = 10). Lowering medium PO2 to 20 torr for 2 min significantly increased cyclic AMP content to 1.13 +/- 0.14 pmol/carotid body (n = 10). This increase was inhibited neither by propranolol (34 microM) nor by propranolol plus haloperidol (27 microM). Inhibition of the cyclic nucleotide phosphodiesterase with 1-methyl-3-isobutylxanthine (0.8 mM) provoked a fast and large increase in cyclic AMP during both control and hypoxic conditions. The cyclic AMP increase induced by hypoxia was still observed when extracellular Ca2+ was absent. Inhibition of the adenylate cyclase by N-(cis-2-phenylcyclopentyl)azacyclotridecan-2-imine hydrochloride (MDL 12330A; 20-1,000 microM) under zero-Ca2+ conditions irreversibly inhibited the cyclic AMP increase produced by hypoxia. Similarly, inhibition of the Ca2(+)-calmodulin complex by trifluoperazine (0.2 mM) or calmidazolium (R 24571; 50-200 microM) prevented the cyclic AMP response. These results suggest that cyclic AMP may be involved in the PO2-sensing mechanism of the carotid body. Hypoxia appears to activate adenylate cyclase directly and independent of any hormone-receptor interactions.

• Authors: M A Delpiano, H Acker
• Journal: Journal of neurochemistry (J Neurochem) Vol. 57 Issue 1 Pg. 291-7 (Jul 1991) ISSN: 0022-3042 [Print] England
• PMID: 1711098 (Publication Type: Journal Article)

Chemical References

• Adenylyl Cyclase Inhibitors
• Phosphodiesterase Inhibitors
• Propranolol
• Cyclic AMP
• 3',5'-Cyclic-AMP Phosphodiesterases
• Haloperidol
• Calcium
• 1-Methyl-3-isobutylxanthine

Topics

• 1-Methyl-3-isobutylxanthine (pharmacology)
• 3',5'-Cyclic-AMP Phosphodiesterases (antagonists & inhibitors)
• Adenylyl Cyclase Inhibitors
• Animals
• Calcium (pharmacology)
• Carotid Body (metabolism)
• Cats
• Cyclic AMP (metabolism)
• Female
• Haloperidol (pharmacology)
• Hypoxia (metabolism, physiopathology)
• In Vitro Techniques
• Male
• Nervous System (physiopathology)
• Phosphodiesterase Inhibitors (pharmacology)
• Propranolol (pharmacology)
• Reference Values