Evidence of NK1 and NK2 tachykinin receptors and their involvement in histamine release in a murine mast cell line.
Binding of [3H]substance P (SP) and histamine release were examined using a cloned mouse mast cell line. SP binding was saturable and specific. In the presence of 30 mM Na2SO4/50 mM Tris buffer, SP interacted with two types of binding sites with Kd values of 0.3 and 40 nM. High-affinity SP binding was blocked by the inclusion of 0.5 uM of the NK1 receptor selective ligand septide in the binding mixture. Neurokinin A (NKA) evoked concentration-dependent histamine release. At concentrations in the nanomolar range, the NK1 preferring agonists SP, SP methylester and physalaemin evoked less than or equal to 5% net release of histamine, which was substantially less than the maximum effect of NKA (+37%) in the micromolar range. Pretreatment of the cells with the NK2 antagonist peptide A reduced NKA-induced histamine release. [D-Arg1,D-Phe5,D-Trp7,9,Leu11]-substance P, a putative SP antagonist, also elicited histamine release in the micromolar range, apparently acting as an agonist at the NK2 site. Compound 48/80, N-terminal SP fragments, neurokinin B and the two selective NK2 receptor antagonists cyclo(Gln-Trp-Phe-(R)-[ANC-2]Leu-Met) (peptide A) and cyclo(Gln-Trp-Phe-Gly-Leu-Met) (peptide B) were ineffective. Although the results suggest the coexistence of functional NK1 and NK2 receptors, it appears that in this mast cell line neurokinin-induced histamine release is primarily mediated by the NK2 receptor, characterized biochemically as a low affinity binding site with a Kd value of 40 nM for SP.
Krumins
S A
SA
Biochemical Pharmacology Branch, United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland 21010.
Broomfield
C A
CA
D000595:Amino Acid Sequence; D000818:Animals; D001667:Binding, Competitive; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D006636:Histamine Release / Q000187:drug effects / Q000502:physiology*; D008407:Mast Cells / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D015288:Neurokinin A / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology; D017981:Receptors, Neurotransmitter / Q000502:physiology*; D018039:Receptors, Tachykinin; D013373:Substance P / Q000378:metabolism / Q000494:pharmacology; D003189:p-Methoxy-N-methylphenethylamine / Q000494:pharmacology
D010446:Peptide Fragments; D010455:Peptides; D017981:Receptors, Neurotransmitter; D018039:Receptors, Tachykinin; C008331:mast cell degranulating peptide; D013373:Substance P; D003189:p-Methoxy-N-methylphenethylamine; D015288:Neurokinin A