LOCALIZATION AND CHARACTERISTICS OF ATRIAL-NATRIURETIC-PEPTIDE RECEPTORS IN PRENATAL AND POSTNATAL RAT-BRAIN
EUROPEAN JOURNAL OF PHARMACOLOGY
Authors: ZORAD, S; TSUTSUMI, K; BHATIA, AJ; SAAVEDRA, JM
Abstract
We studied the expression of atrial natriuretic peptide (ANP) receptor subtypes during development in the rat forebrain, using quantitative autoradiography. Highest ANP binding was observed in the cortical neuroepithelium at embryonic day 17. Lower ANP binding was found in cingulate and frontal cortices at postnatal day 10, but none was detectable at 8 weeks of age. In the neuroepithelium of the embryonic rat, binding was displaced with a potency of rat ANP-(1-28) (rANP) > porcine type-C natriuretic peptide (pCNP-22) = rat ANP fragment C-ANP-(4-23) (rC-ANP-(4-23)) = rat brain natriuretic peptide (rBNP-32), different from that of any of the well-characterized (ANP(A), ANP(B), and ANP(C)) natriuretic peptide receptors. The present results support the hypothesis of a role for ANP during brain maturation and indicate that the ANP receptors highly expressed in the embryonic neuroepithelium may belong to a new ANP receptor subtype not yet characterized.
Lanthanum-Catalyzed Double Hydrophosphinylation of Nitriles
ORGANOMETALLICS
Authors: Basiouny, Miriam M. I.; Schmidt, Joseph A. R.
Abstract
A new lanthanum-based catalyst was shown to be effective for the double hydrophosphinylation of unactivated nitriles under very mild conditions. Surprisingly, the lanthanum catalyst gave two regioisomeric products depending on the nature of the starting nitrile. Primary alkyl nitriles undergo 1,1-addition to give products with a new PCP linkage and concomitant formation of a primary amine. Under the same conditions, secondary alkyl and aryl nitriles instead produced 1,2-addition products, where 1 equiv of the phosphine oxide was added to the carbon, while a second equivalent added to the nitrogen of the nitrile, resulting in a PCNP framework. Further investigation of the catalytic cycle yielded evidence that all nitriles first undergo 1,1-addition (deemed the kinetic product) that then undergoes isomerization to the final unsymmetric addition product (the thermodynamic product). All catalytic reactions were run neat or with very little solvent, required little workup, and had high to moderate yields.