A 78-year-old woman presented to the emergency room complaining of a 2-week history of general fatigue and increasing weakness in both legs. She also experienced an irregular heartbeat and had slight dyspnea. She had had a cardiac syncope 1 year earlier and received a pacemaker (VVI mode). The woman reported a history of arterial hypertension and mild chronic heart failure. Because of previous ...

Yohimbine is a potent and relatively nonselective 2-adrenergic receptor (AR) antagonist. In an earlier report, we demonstrated that dimeric yohimbine analogs containing methylene and methylene-diglycine tethers were highly selective human 2C-AR ligands. Little work has been done to examine the role of the tether group or the absence of the second yohimbine pharmacophore on selectivity for human...

Presynaptic inhibition of transmitter release is commonly mediated by a direct interaction between G protein subunits and voltage-activated Ca channels. To search for an alternative pathway, the mechanisms by which presynaptic bradykinin receptors mediate an inhibition of noradrenaline release from rat superior cervical ganglion neurons were investigated. The peptide reduced noradrenaline relea...

Although serotonin 5-HT1A receptors couple to several Gi/o Gprotein subtypes, little is known concerning their differential activation patterns. In this study, in membranes of Chinese hamster ovary cells expressing h5-hydroxytryptamine1A receptors (CHOh5-HT1A), isotherms of 5-HT-stimulated guanosine-5 -O-(3[S]thio)-triphosphate ([S]GTP S) binding were biphasic, suggesting coupling to multiple G...

To explore the feasibility of developing inhibitors of signaling by opioid receptors and other G protein-coupled receptors (GPCRs) that use the same G protein pool, we investigated the capacity of a minigene encoding the third intracellular loop of the -opioid receptor ( -i3L) to act as competitive antagonist of the receptor-G protein interface interaction. In -i3L-expressing cells, the peptide...