piperidines and 2-aminoisobutyric-acid

A new optically inactive 3(10)-helical peptide with a side-chain cross-linking was found to exhibit chiral memory stored in the peptide backbone, whose chirality was induced by a noncovalent interaction of a chiral molecule at the N-terminal end of the peptide.

Topics: Aminoisobutyric Acids; Circular Dichroism; Kinetics; Nuclear Magnetic Resonance, Biomolecular; Oligopeptides; Phenylalanine; Piperidines; Protein Structure, Secondary; Stereoisomerism

Dually perfused human placental lobules were employed to study the effects of vesamicol (an inhibitor of acetylcholine (ACh) storage) and physostigmine (an inhibitor of cholinesterase breakdown of ACh) on ACh output from fetal vessels and on materno-fetal transfer of the nonmetabolizable amino acid alpha-aminoisobutyric acid (AIB). Bilateral perfusion with vesamicol (100 mumol L-1) or omission of physostigmine (2 x 7 mumol L-1) from the perfusate significantly reduced the output of ACh. However, neither drug had any significant effect on AIB transfer. Thus, the results of this study do not provide evidence for a close relationship between the placental cholinergic system and materno-fetal AIB transfer.

Topics: Acetylcholine; Aminoisobutyric Acids; Biological Transport; Female; Humans; Maternal-Fetal Exchange; Perfusion; Physostigmine; Piperidines; Placenta; Pregnancy