Biomedical subjects

S Danti

Publications and source records attributed to S Danti.

7 recordsLinked to original sources

PubMed1989

Effect of tricyclic antidepressant drugs in the isolation-induced social behavioural deficit test.

1. Mice were isolated for 7-9 days. An isolated mouse and a mouse reared in group show a difference in their behaviour when observed together under an inverted beaker. The isolated mouse makes one half escape attempts in regard to the grouped mouse. This is considered as a social behavioural deficit. 2. The effect of four tricyclic antidepressant drugs was tested on this social behavioural deficit. None of the following drugs acutely given: imipramine, desipramine, amitriptyline impaired the social behavioural deficit. Clomipramine reduced the deficit at the only dose of 2 mg/kg. The four antidepressants tended to increase the deficit at the high dose of 32 mg/kg but this may reflect a sedative effect. Chronic amitriptyline did not impair the social behavioural deficit. 3. It is concluded that acute and probably also chronic antidepressant treatments are without effect on the isolation induced social behavioural deficit test.

Amitriptyline↗

PubMed1987

Noradrenergic rather than GABAergic processes as the common mediation of the antidepressant profile of GABA agonists and imipramine-like drugs in animals.

The present study was aimed at investigating in rats whether a common mechanism might underlie the reversal of depressive-like behaviors by classical antidepressants and by GABA agonists such as muscimol. Blockade of GABA transmission with picrotoxin (1 mg/kg IP) abolished the muscimol (0.5-1 mg/kg)-induced reduction of immobility in the swimming test and the reversal of escape failures in the learned helplessness paradigm. Conversely, picrotoxin was found not to reduce the efficacy of imipramine-like drugs in these same animal models. The combination of muscimol and tricyclics given at subeffective doses resulted in behavioral changes that can be accounted for by an additive interaction between these two classes of drugs. These data confirm the antidepressant-like profile of GABA agonists but suggest that it is unlikely that the primary antidepressant mechanism of conventional antidepressants involves GABA-A receptors. In the swimming test, prazosin (2 mg/kg), an alpha adrenoceptor blocker, antagonized the reduction of immobility produced by both muscimol and imipramine-like drugs. In the learned helplessness paradigm, penbutolol (0.25-0.5 mg/kg) and, though to a lesser extent prazosin, counter-acted the reversal of escape failures caused by muscimol and imipramine. On the basis of these data, it is tempting to speculate that increased transmitter outflow at noradrenergic receptors may be an essential component in the mechanism of action of imipramine-like drugs but also of GABA agonists.

Animals↗

PubMed1987

Beta-adrenergic agonists reduce spontaneous motor activity through either beta 1 or beta 2 receptors.

In mice, the clenbuterol-induced decrease in spontaneous motor activity was antagonized by IPS-339 (beta 2 antagonist) but not by betaxolol (beta 1 antagonist), whereas the isoproterenol-induced decrease in spontaneous motor activity was completely antagonized by betaxolol and only partially by IPS-339. It can be concluded that the clenbuterol-induced decrease in spontaneous motor activity is of the beta 2-type, whereas that induced by isoproterenol is essentially of the beta 1 type. In addition, chronic treatment with clenbuterol induced a tachyphylaxis to the effect of clenbuterol but not of isoproterenol. After chronic administration of tricyclic antidepressants (imipramine and desipramine) the number of cortical beta 1 adrenergic receptors decreased without impairing the clenbuterol-induced decrease in spontaneous motor activity. We conclude that beta 2 adrenergic receptors mediate the clenbuterol-induced decrease in spontaneous motor activity and the tachyphylaxis to this effect after chronic treatment.

Adrenergic beta-Agonists↗

PubMed1986

Acute versus repeated administration of desipramine in rats and mice: relationships between brain concentrations and reduction of immobility in the swimming test.

Immobility scores in the swimming test and brain concentrations of desipramine were determined in rats and mice following repeated injection of the antidepressant versus acute administration of either a behaviorally effective or ineffective dose of the drug. Five injections (IP) of desipramine (each injection being performed at the measured T1/2 of the drug in the brain) reduced immobility scores by 30%, whereas this regimen resulted in brain drug concentrations not different from those obtained after a single, behaviorally ineffective dose of desipramine. It is suggested that the enhanced "antidepressant" response such as that frequently observed in animals after repeated injection of imipramine-like drugs does not involve accumulation of the drug in the brain.

Animals↗

PubMed1984

Disappearance of the decrease in biting behavior induced by clenbuterol, a beta-adrenergic agonist, after chronic administration.

The beta-adrenergic agonist clenbuterol decreased interest in food in starved mice, 30 minutes after administration. This effect disappeared after repeated treatment with clenbuterol (0.25 mg/kg, twice daily). Three chronic injections were sufficient to prevent the effect of an acute dose of clenbuterol (0.125 mg/kg) up to 45 hours after treatment.

Aggression↗

PubMed1983

Attempt at pharmacological differentiation of central beta-adrenergic receptors.

The beta-adrenergic stimulants isoprenaline, salbutamol and clenbuterol decreased motor activity, reduced the interest of fasting mice in food pellets ('Tantale' test), and antagonized high-dose apomorphine hypothermia. Clenbuterol was 16--60 times more potent than the other two agonists in all tests, apparently because of better crossing into the C.N.S. The beta-adrenergic blockers, d,l-propranolol and l-penbutolol, completely antagonized the effects of salbutamol and clenbuterol in tests of motor activity and apomorphine hypothermia, penbutolol being 30--60 times more active than propranolol, perhaps due to its greater lipid solubility. The Tantale test allows unambiguous differentiation between penbutolol and propranolol. While the first completely blocked the effects of clenbuterol and salbutamol, the second was effective only within a narrow dose range. Finally, the dose-effect relationships of the 3 agonists were parallel in the Tantale test, while they were divergent in the other two. This suggests that different classes of beta-adrenergic receptors may be involved in the various test.

Adrenergic beta-Agonists↗

PubMedDate not supplied

[Primary intestinal lymphangiectasis. A case treated surgically].

The authors describe a rare case of primary intestinal lymphangiectasis resolved with surgical treatment. Usually the natural course of the disease is relatively mild and medical nutritional treatment can be sufficient. In this case the lymphatic intestinal anomaly was generalized to the entire small intestine but a distal ileal segment was particularly involved. The surgical resection of this intestinal tract resolved the symptomatology.

Age Factors↗