The cyclic AMP response to noradrenalin in young adult rat brain following post-natal injections of 6-hydroxydopamine

Cyclic AMP in cerebrospinal fluid of manic and depressive patients

Cyclic 3',5'-adenosine monophosphate (c-AMP) was measured in cerebrospinal fluid (CSF) of manic and depressive patients with and without probenecid administration both before and during treatment with various psychotropic drugs. Oral probenecid (100 mg/kg) produced substantial c-AMP accumulations in CSF suggesting a probenecid-sensitive transport mechanism for c-AMP. Baseline and probenecid-induced accumulations of c-AMP were not significantly different in manic and depressed patients, while baseline levels in depressed patients were higher than those in neurological controls. Imipramine, amitriptyline, lithium, tryptophan, and electroconvulsant therapies did not significantly alter levels or accumulations of c-AMP in CSF of depressed patients.

Pre- and post-junctional supersensitivity: differentiation by intraventricular infusions of norepinephrine and methoxamine

Intraventricular infusions of methoxamine, an adrenergic agonist that has a relatively low affinity for the presynaptic uptake mechanism, produces a significant dose-dependent increase in locomotor activity comparable to the increase elicited by infusion of equimolar doses of norepinephrine (NE). The behavioral responsiveness to infusion of both NE and methoxamine was more than doubled 3 weeks after pretreatment with 6-hydroxydopamine (6-OHDA). These results indicate that the increased responsiveness to NE induced by 6-OHDA is due to enhanced postsynaptic receptor sensitivity rather than to a loss of presynaptic uptake inactivation.