title: A comparison of the release of substance P and some synthetic analogues from micropipettes by microiontophoresis or pressure.
abstract: The release of substance P (SP) and two analogues by iontophoresis or pressure from microelectrodes was compared. Substance P was released linearly by iontophoresis from electrodes while no release of the analogues was detected. [N-methylphenylalanine8, N-methylglycine9-] SP5-11 (DiMeC7) and [methyl-2-aminoethyl]11 SP (SP-DAE) were released from electrodes by pressure ejection with linear relationships in all cases between pressure and the amounts released. Under the tested experimental conditions, release of substance P by iontophoresis was between 2 and 3 orders of magnitude less than that by pressure over a given time. The release of substance P and the uncharged analogue DiMeC7 by pressure was very similar while release of SP-DAE was one order of magnitude less.
mesh_terms: D004586:Electrophoresis / Q000379:methods; D007478:Iontophoresis; D010446:Peptide Fragments; D011312:Pressure; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D013373:Substance P / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000032:analysis*
chemical_list: D010446:Peptide Fragments; D013373:Substance P; C032720:substance P (5-11), pGlu(5)-MePhe(8)-MeGly(9)-; C039019:substance P, aminoethyl(2)-Met(11)-; D011761:Pyrrolidonecarboxylic Acid