Background—Activation of the sympathetic nervous system has important prognostic implications in chronic heart failure. Nonselective versus selective b-adrenergic receptor antagonists may have differential effects on norepinephrine release from nerve terminals mediated by prejunctional b2-adrenergic receptors. Methods and Results—Thirty-six patients with chronic heart failure were randomized to...

Chronic (3-day) treatment with prazosin causes an increase in renal a2-adrenergic receptor density and the relocation of renal tubular a2-adrenergic receptors from extrajunctional to postjunctional sites. We investigated whether chronic prazosin treatment (2 mg/kg, i.p.) caused a functional alteration of other renal a2-adrenergic receptors, using the isolated perfused rat kidney. Prazosin signi...

The ascending reflex contraction of the small intestine involves predominantly cholinergic neurotransmission. The orally projecting neural excitatory pathway of the myenteric reflex was studied in an in vitro model of rat ileal segments. The contractile response elicited by aboral field stimulation was significantly inhibited by a range of muscarinic receptor antagonists. Methoctramine and trip...