Comparative evaluation of the effects of labetalol, verapamil and diltiazem on antipyrine and indocyanine green clearances.
Standard measurements of C. elegans swimming utilizes manual assessments of the number of animals exhibiting swimming versus paralysis. Our approach deconstructs the time course and rates of movement in an automated fashion, offering a significant increase in the information that can be obtained from swimming behavior.
Platelet serotonin uptake and 3H-imipramine binding were measured in eight patients with panic disorders and nine controls. The Vmax of serotonin uptake was significantly elevated in patients compared to controls (77 +/- 14 vs. 50 +/- 4 pmol/10(8) platelets/min; P less than 0.05) while Km values were not different (1.46 +/- 0.41 vs. 1.24 +/- 0.20 microM). 3H-Imipramine binding to ruptured platelet membranes was not significantly different between patients and controls for either Bmax (395 +/- 71 vs. 412 +/- 107 fmol/mg protein) or Kd (0.90 +/- 0.18 vs. 1.09 +/- 0.30 nM). The implications for a serotonergic dysfunction in panic disorders are discussed.
The authors examined whether long-term treatment with imipramine would decrease CO2-induced anxiety in 10 patients with panic disorder. The patients underwent CO2 testing after single-blind placebo testing and again after imipramine treatment. Scores on self-rated visual analog mood scales and panic attack symptom scales showed that the anxiogenic effects of CO2 were significantly reduced during long-term imipramine treatment. These results suggest that the mechanisms underlying CO2-induced anxiety may be similar to those involved in the pathophysiology of panic disorder.
A number of 5-hydroxytryptamine (5-HT) uptake inhibitors have been shown to displace the binding of [3H]imipramine to rat cortical membranes in a complex manner with Hill slopes less than unity. Norzimeldine displaced the binding of [3H]imipramine in a biphasic manner with IC50 values for the two components of about 30 nM and 30 microM. This latter site alone was found in tissues that had been treated with a protease. Binding to both of these sites was displaced by 10 microM desipramine. The protease-sensitive [3H]imipramine binding sites were found to be saturable, high-affinity binding sites with a KD of 8 nM. The number of these sites varied between brain regions and was positively correlated with the regional distribution of [14C]5-HT but not [3H]noradrenaline uptake. This was not the case however for the protease-resistant but desipramine-displaceable binding sites. Since most previous [3H]imipramine binding studies have been performed with high concentrations of desipramine (10 microM) to define "specific binding," these data would suggest that either protease-sensitivity or displacability by 1 microM norzimeldine would give more reliable estimates of the specific binding.
To evaluate the efficacy and tolerability of sertraline and imipramine in patients with comorbid panic disorder and major depressive disorder.
(1) The low, middle and high dosages of MC (i.g.) significantly reduced the immobility time of mice in forced swimming test (P<0.05). (2) MC in dosages of 10 mg/kg and 20 mg/kg prevented the lowering of temperature induced by reserpine (P<0.05), while 40 mg/kg had no significant effects on it (P>0.05). (3) With acute administration (3 days), the low, middle and high dosagey of MC (i.g.) significantly inhibited the activity of MAO-A in hippocampus (P<0.01), and the high dosage significantly inhibited the activity of MAO-A in hypothalamus (P<0.01), while the 3 dosages had no significant effects on the activity of MAO-A in cortex (P>0.05). With chronic administration (21 days), MC in 3 dosages had no significant effects on the activities of MAO-A in cortex and hypothalamus (P>0.05), and the high dosage (40 mg/kg) significantly enhanced the activity of MAO-A in hippocampus (P<0.01). (4) With acute administration, MC in dosages of 10 mg/kg and 20 mg/kg significantly inhibited the activity of MAO-B in cortex (P>0.05), and MC in dosage of 10 mg/kg significantly inhibited the activity of MAO-B in hypothalamus (P<0.05), and MC in dosage of 20 mg/kg significantly enhanced the activity of MAO-B in hippocampus (P<0.01). With chronic administration, MC of 3 dosages produced no significant effects on the activities of MAO-B in 3 different rat brain regions (P>0.05).
The effects of various alpha 2 adrenoceptor agonists on forced swimming-induced despair behaviour were studied in mice. Clonidine, B-HT 920 and guanfacine significantly prolonged the total immobility duration. Clonidine-induced behavioural despair was antagonized by prior treatment with yohimbine. The tricyclic antidepressants imipramine, desipramine, trimipramine, amitriptyline, nortriptyline and doxepin, the MAO inhibitor tranylcypromine, and the antimanic agent lithium reversed clonidine-induced behavioural despair. Chronic treatment with imipramine evoked more pronounced reversal as compared to acute treatment. Amphetamine, a psychostimulant, inhibited clonidine-induced enhancement of immobility duration but diazepam, a skeletal muscle relaxant was without any effect. On the other hand, adenosine showed potentiation of the submaximal response of clonidine. These observations suggest that clonidine-induced behavioural despair is probably mediated through its presynaptic action on alpha 2 adrenoceptors, resulting in reduced central noradrenergic outflow. The present data proposes a simple test system to induce depression-like syndrome in animals, sensitive to antidepressant therapy.