Reduced L-type calcium current in the embryonic chick heart with persistent truncus arteriosus.

Abstract

Calcium currents were examined in an experimental model in the embryonic chick heart with a congenital malformation known as persistent truncus arteriosus. This is a severe defect characterized by failure of conotruncal and aorticopulmonary septation of the embryonic heart tube. As a result, no separation into the aortic and pulmonary arteries occurs, and there is a common outflow tract. The hearts with persistent truncus arteriosus had a 26% greater ventricular to whole embryo weight, which indicated that the ventricles were enlarged. Both the low-threshold T-type (ICa.T) and the 1,4-dihydropyridine-sensitive L-type (ICa.L) Ca2+ currents were present in the ventricular myocytes from hearts at day 11 of incubation. However, day 11 hearts with persistent truncus arteriosus showed a twofold reduction in the peak magnitude of ICa.L at a test potential of + 10 mV without a concomitant reduction in the number of L channels detected by 1,4-dihydropyridine antagonist [(+)[3H]PN200-110] and agonist (Bay K 8644) receptor binding. The results indicated that an L channel regulatory mechanism other than protein synthesis was affected. These changes are consistent with responses to conditions of excessive hemodynamic burden that have been characterized in adult hearts.

• Authors: T L Creazzo
• Journal: Circulation research (Circ Res) Vol. 66 Issue 6 Pg. 1491-8 (Jun 1990) ISSN: 0009-7330 [Print] United States
• PMID: 1693103 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Calcium Channel Blockers
• Calcium Channels
• Oxadiazoles
• Receptors, Nicotinic
• 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester
• Calcium
• Isradipine

Topics

• 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester
• Animals
• Calcium (physiology)
• Calcium Channel Blockers (metabolism)
• Calcium Channels
• Chick Embryo
• Electrophysiology
• Heart (physiopathology)
• Isradipine
• Myocardium (metabolism)
• Oxadiazoles
• Receptors, Nicotinic (metabolism)
• Truncus Arteriosus, Persistent (embryology, physiopathology)