Background—Autoantibodies directed against the b1-adrenergic receptor have been described in patients with dilated cardiomyopathy. These autoantibodies exert an agonistic, chronotropic effect on spontaneously beating cultured neonatal rat cardiomyocytes. We studied the effect of such antibodies on b1-adrenergic receptor expression. Methods and Results—Cardiomyocytes were incubated with either t...

Primary adipocytes were isolated from axillary brown adipose tissue from adult cynomolgus monkeys. That this tissue contained brown adipocytes was verified by morphological examination and by demonstrating the presence of uncoupling protein messenger ribonucleic acid in the isolated adipocytes. The contributions of beta 1-, beta 2-, and beta 3-adrenergic receptors (AR) to lipolysis and oxygen c...

Conditions have been developed for desensitizing the beta-adrenergic receptor-coupled adenylate cyclase of turkey erythrocytes in a cell-free system. Desensitization is observed when cell lysates are incubated with isoproterenol or cAMP analogs for 30 min at 37 degrees C. Maximally effective concentrations of isoproterenol produce a 41.0 +/- 1.55% loss of iosproterenol-stimulated and a 15.0 +/-...

Interactions between noradrenergic and cholinergic receptor signaling may be important in some forms of learning. To investigate whether noradrenergic and cholinergic receptor interactions regulate forms of synaptic plasticity thought to be involved in memory formation, we examined the effects of concurrent beta-adrenergic and cholinergic receptor activation on the induction of long-term potent...

Identification of endogenous toxins and characterization of the mechanisms by which toxins produce cell injury and death may help understand both normal modeling of cell populations and connections in the CNS as well as abnormal cell loss. The toxicity of catecholamines intrinsic to the CNS was investigated using the model system of rat cerebral cortex in dissociated cell culture. All catechola...

The influence of various adrenergic agonists and antagonists on pyruvate kinase activity and lactate production from endogenous glycogen reserves was investigated in hepatocytes isolated from young and old rats. With hepatocytes prepared fromjuvenile rats (100 to 150 g) 10 PM epinephrine and 10 pM isoproterenol (a padrenergic agonist) inhibit pyruvate kinase activity and lactate production; whe...

The role of thyroid hormones (TH) in the normal functioning of adult mammalian brain is unclear. Our studies have identified synaptosomal Na(+)-K(+)-ATPase as a TH-responsive physiological parameter in adult rat cerebral cortex. L-triiodothyronine (T3) and L-thyroxine (T4) both inhibited Na(+)-K(+)-ATPase activity (but not Mg(2+)-ATPase activity) in similar dose-dependent fashions, while other ...