Autoradiographic visualization and characteristics of [125I]bradykinin binding sites in guinea pig brain
Autor: | David R. Hill, C. Robin Hiley, Philip J. Privitera, P. Daum |
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Rok vydání: | 1992 |
Předmět: |
medicine.medical_specialty
medicine.drug_class Guinea Pigs Bradykinin Biology Iodine Radioisotopes chemistry.chemical_compound Radioligand Assay Internal medicine medicine Animals Bradykinin receptor Binding site Molecular Biology Brain Chemistry General Neuroscience Receptors Bradykinin Area postrema Spinal trigeminal nucleus Solitary tract Receptor antagonist Receptors Neurotransmitter Dorsal motor nucleus Endocrinology medicine.anatomical_structure chemistry Autoradiography Neurology (clinical) Developmental Biology |
Zdroj: | Brain research. 577(1) |
ISSN: | 0006-8993 |
Popis: | The present study was undertaken to localize and characterize bradykinin (BK) binding sites in 10 microns serial sections of guinea pig brain by in vitro quantitative receptor autoradiography. Specific binding of [125I-Tyr8]bradykinin ([125I]BK) was localized in the medulla oblongata to the regions of the nucleus of the solitary tract (nTS), the area postrema (AP), the dorsal motor nucleus of the vagus (X) and the caudal subnucleus of the spinal trigeminal nucleus. No significant specific [125I]BK binding was seen in other brain regions. The specific binding (85-90% of total binding) was of high affinity and saturable with a KD of 73.5 +/- 9.9 pM and a Bmax of 27.8 +/- 1.9 amol per mm2 of tissue. In competition studies, the rank order of potencies was: BK greater than Met-Lys-BK greater than Lys-BK much greater than Des-Arg9-BK. The B2 receptor antagonist D-Arg0-Hyp3-Thi5,8-D-Phe7-BK inhibited [125I]BK binding with a Ki value of 3.5 +/- 1.5 nM while Des-Arg9-[Leu8]-BK, a B1 receptor antagonist did not significantly inhibit [125I]BK binding in concentrations up to 10 microM. Our finding of specific high affinity [125I]BK binding sites in the nTS, AP and the X is important because these brain areas are known to be involved in central cardiovascular regulation. Moreover, our results suggest that the specific [125I]BK binding sites in the guinea pig medulla are of the bradykinin B2 receptor type. |
Databáze: | OpenAIRE |
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