Guanosine-5'-(3-O-thio)triphosphate-mediated stimulation of phosphoinositidase C in solubilized rat peripheral nerve myelin and its alteration in streptozotocin-induced diabetes.


Journal Article

The regulation of phosphoinositidase C (PIC) activity by guanosine-5'-(3-O-thio)triphosphate (GTP gamma S) was characterized in a cholate-solubilized peripheral myelin-enriched fraction from rat sciatic nerve. The GTP analog maximally enhanced PIC-catalyzed hydrolysis of exogenous phosphatidylinositol-4,5-bisphosphate (PIP2) in a dose-dependent manner only within a narrow range of cholate concentrations. Maximal stimulation was attained at 0.6 microM GTP gamma S and could be completely prevented by 1 microM guanosine-5'-(2-O-thio)diphosphate. Neither adenylyl-imidodiphosphate nor adenosine triphosphate (ATP) enhanced PIC activity. Carbamoylcholine (1 mM) added together with GTP gamma S increased the extent of PIP2 hydrolysis over that elicited by GTP gamma S alone and this stimulation was blocked by the muscarinic receptor antagonist, atropine (50 microM). In detergent-solubilized myelin preparations from streptozotocin-induced diabetic rats, a higher concentration of the guanine nucleotide analog was required to achieve stimulation comparable to that obtained with corresponding preparations from normal animals. These results suggest that sciatic nerve myelin possesses muscarinic receptors coupled via a GTP-binding protein to PIC and that this system can be reconstituted in detergent-solubilized extracts. It is possible that the function of G proteins in cell signaling is impaired in experimental diabetic neuropathy.

Full Text

Cited Authors

  • Mathew, J; Eichberg, J

Published Date

  • January 1, 1994

Published In

Volume / Issue

  • 37 / 1

Start / End Page

  • 83 - 91

PubMed ID

  • 8145305

Pubmed Central ID

  • 8145305

Electronic International Standard Serial Number (EISSN)

  • 1097-4547

International Standard Serial Number (ISSN)

  • 0360-4012

Digital Object Identifier (DOI)

  • 10.1002/jnr.490370111


  • eng