PT  - JOURNAL ARTICLE
AU  - C M Lee
AU  - J A Javitch
AU  - S H Snyder
TI  - 3h-substance P binding to salivary gland membranes. Regulation by guanyl nucleotides and divalent cations.
DP  - 1983 May 01
TA  - Molecular Pharmacology
PG  - 563--569
VI  - 23
IP  - 3
4099  - http://molpharm.aspetjournals.org/content/23/3/563.short
4100  - http://molpharm.aspetjournals.org/content/23/3/563.full
SO  - Mol Pharmacol1983 May 01; 23
AB  - With appropriate measures to protect 3H-substance P (3H-SP) from proteolytic degradation and from nonspecific adsorption to glass-fiber filters, we have been able to demonstrate reliably a high-affinity specific binding of 3H-SP to rat submaxillary/sublingual gland membranes with a KD of 1 nM and Bmax of 6 pmoles/g of tissue. The relative potencies of various SP fragments and related analogues in reducing 3H-SP binding parallel their potencies in stimulating phosphatidylinositol turnover, amylase release, and salivation, thus supporting an association of the observed 3H-SP binding site with the physiological SP receptors in this tissue. This binding is selectively stimulated by some divalent cations (Mn2+ greater than Mg2+ greater than Ca2+) but inhibited by several guanyl nucleotides, suggesting a possible linkage to adenylate cyclase. However, no effect of SP on either the basal or the norepinephrine-stimulated adenylate cyclase activity could be demonstrated in salivary gland homogenates.