Specific inhibition of long-lasting, L-type calcium channels by synthetic parathyroid hormone

Journal Article · Mon Jan 01 04:00:00 EST 1990 · Proceedings of the National Academy of Sciences of the United States of America; (USA)

DOI:https://doi.org/10.1073/pnas.87.2.623· OSTI ID:6700159

Pang, P K.T.; Wang, R; Shan, J; Karpinski, E; Benishin, C G ^[1]

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1. Univ. of Alberta, Edmonton (Canada)

The effect of an active synthetic N-terminal fragment of bovine parathyroid hormone (bPTH), bPTH-(1-34), on Ca{sup 2+} channels was studied in mouse neuroblastoma cells (N1E-115). With the whole-cell variation of the patch-clamp technique, T (transient) and L (long-lasting) types of Ca{sup 2+} currents were identified. Pharmacological characterization showed that the L current was amplified by the Ca{sup 2+} channel stimulator BAY K-8644, but the T current was unaffected. The administration of bPTH-(1-34) produced dose-related inhibition of the L current, which could be reversed by BAY K-8644. The peptide had no effect on the T current. In addition, use of the fluorescent indicator fura-2 showed that bPTH-(1-34) inhibited the KCl-stimulated increase in intracellular free Ca{sup 2+} in neuroblastoma cells with L channels but not in cells with T channels. An inactivated (oxidized) preparation of bPTH-(1-34) failed to affect the L current. High-affinity binding of labeled PTH analog to these neuroblastoma cells was also demonstrated. In addition, bPTH-(1-34) inhibited the L current in cultured vascular smooth muscle cells from rat tail artery. These data indicate that, in some tissues PTH can act as an endogenous blocker of Ca{sup 2+} entry.

• OSTI ID: 6700159
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (USA), Journal Name: Proceedings of the National Academy of Sciences of the United States of America; (USA) Vol. 87:2; ISSN 0027-8424; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALINE EARTH METAL COMPOUNDS
ANIMAL CELLS
ANIMALS
BIOELECTRICITY
CALCIUM COMPOUNDS
CATIONS
CATTLE
CHARGED PARTICLES
CHEMICAL REACTIONS
CROSS-LINKING
DOMESTIC ANIMALS
DOSE-RESPONSE RELATIONSHIPS
ELECTRIC POTENTIAL
ELECTRICITY
FLUORESCENCE
HORMONES
INHIBITION
IONS
LUMINESCENCE
MAMMALS
MEMBRANE TRANSPORT
MICE
MUSCLES
PARATHORMONE
PEPTIDE HORMONES
PHARMACOLOGY
POLYMERIZATION
RODENTS
RUMINANTS
TUMOR CELLS
VERTEBRATES