Desensitization of substance P-induced K+ release in rat parotid.
Challenge of rat parotid slices with substance P or its analogs, at concentrations which cause less than maximal response resulted in the transient release of K+ into the medium. Reuptake of the released K+ into the cell was accompanied by a parallel decrease in the biologically active concentration of the peptide in the medium, indicating that at low concentrations inactivation of the peptide is a mechanism for termination of the substance P response. At concentrations of substance P and its analogs which are higher than needed for a maximal response, a second mechanism for the termination of the response enters into play, resulting in desensitization of the response to substance P. Desensitization was specific for substance P and was not influenced by activation of the cholinergic or alpha-adrenoceptors. Inactivation of the peptide by proteolytic breakdown does not take part in the development of desensitization to substance P.
Friedman
Z Y
ZY
Wormser
U
U
Rubini
E
E
Chorev
M
M
Gilon
C
C
Selinger
Z
Z
D000818:Animals; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D009842:Oligopeptides / Q000494:pharmacology; D010276:Parasympatholytics / Q000494:pharmacology; D010306:Parotid Gland / Q000187:drug effects / Q000378:metabolism*; D010446:Peptide Fragments; D011188:Potassium / Q000378:metabolism*; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D051381:Rats; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects; D013268:Stimulation, Chemical; D013373:Substance P / Q000494:pharmacology* / Q000031:analogs & derivatives; D013997:Time Factors
D009842:Oligopeptides; D010276:Parasympatholytics; D010446:Peptide Fragments; D011942:Receptors, Adrenergic, alpha; D013373:Substance P; C026238:substance P (6-11), pGlu(6)-; D011188:Potassium; D011761:Pyrrolidonecarboxylic Acid