PT - JOURNAL ARTICLE AU - J A Miller AU - N L Velayo AU - R C Dage AU - D Rampe TI - High affinity [3H]glibenclamide binding sites in rat neuronal and cardiac tissue: localization and developmental characteristics. DP - 1991 Jan 01 TA - Journal of Pharmacology and Experimental Therapeutics PG - 358--364 VI - 256 IP - 1 4099 - http://jpet.aspetjournals.org/content/256/1/358.short 4100 - http://jpet.aspetjournals.org/content/256/1/358.full SO - J Pharmacol Exp Ther1991 Jan 01; 256 AB - We examined the binding of the antidiabetic sulfonylurea [3H] glibenclamide to rat brain and heart membranes. High affinity binding was observed in adult rat forebrain (Kd = 137.3 pM, maximal binding site density = 91.8 fmol/mg of protein) and ventricle (Kd = 77.1 pM, maximal binding site density = 65.1 fmol/mg of protein). Binding site density increased approximately 250% in forebrain membranes during postnatal development but was constant in ventricular membranes. Quantitative autoradiography was used to examine the regional distribution of [3H] glibenclamide binding sites in sections from rat brain, spinal cord and heart. The greatest density of binding in adult brain was found in the substantia nigra and globus pallidus, whereas the other areas displayed heterogenous binding. In agreement with the membrane binding studies, 1-day-old rat brain had significantly fewer [3H]glibenclamide binding sites than adult brain. Additionally, the pattern of distribution of these sites was qualitatively different from that of the adult. In adult rat spinal cord, moderate binding densities were observed in spinal cord gray and displayed a rostral to caudal gradient. In adult rat heart, moderate binding densities were observed and the sites were distributed homogeneously. In conclusion, significant development of [3H]glibenclamide binding sites was seen in the brain but not the heart during postnatal maturation. Furthermore, a heterogeneous distribution of binding sites was observed in both the brain and spinal cord of adult rats.