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Common effects of four beta-adrenergic blocking drugs have been investigated in mice using classical and new psychopharmacological tests. Propranolol, alprenolol, practolol and penbutolol reduced the increase in locomotor activity produced by reserpine after MAO inhibition; they produce hypothermia when associated with amphetamine and they increase oxotremorine-induced hypothermia. Regarding these three tests the studied substances ranged themselves in the same order of potency: penbutolol > propranolol > alprenolol > practolol. Propranolol and penbutolol decreased the toxicity provoked in crowded mice by amphetamine or by the association pargyline-reserpine; alprenolol and practolol did not. Propranolol, penbutolol and alprenolol antagonized the amphetamine-induced increase in motor activity; practolol did not. When used at doses for which d-l propranolol was active, the dextrogyre isomer of propranolol was without effect whatever the test studied. It is suggested that for the selection of a beta-blocking drug, regarding central effects in man, the tests described would deserve consideration.

Male Wistar rats were trained to press a lever with food reinforcement according to a continuously reinforced schedule (CRF). Afterwards, rats were subjected to three experimental sessions (30 min each) during which responding was rewarded according to a progressive ratio schedule (following an initial 2-min CRF period, the number of presses necessary for the pellet delivery was doubled every second minute). Responding during the first half of each session, i.e., pressing for food, was maintained at a significant level, whereas it was almost suppressed during the second part of the session. As compared to controls (200 +/- 20 presses/30 min) animals given amfonelic acid (0.5, 1 mg/kg IP), methylphenidate (4, 8 mg/kg IP), caffeine (16 mg/kg IP), cocaine (4 mg/kg IP), oxolinic acid (32 mg/kg IP), nomifensine (4 mg/kg IP), DR 250 (2, 4 mg/kg IP) and d-amphetamine (0.25, 0.5, 1 mg/kg IP) showed an increased rate of responding ranging from 400 to 950 presses/30 min. In contrast, apomorphine, MK 486 + L-dopa, trihexyphenidyl, imipramine, salbutamol and diazepam did not increase responding. These results suggested that this test is highly sensitive for psychomotor stimulants and perhaps for their ability to enhance the reinforcing value of the reward or stimuli associated with the reward. Such activity seemed related to a catecholaminergic substrate since the increase of responding induced by amphetamine was blocked by pimozide, d,l-propranolol and prazosin.

The antagonism of hypothermia induced by two doses of apomorphine (1 to 16 mg/kg) is proposed as an improved screening test for both neuroleptics and antidepressants. Low dose apomorphine-induced hypothermia (1 mg/kg) differentiates sulpiride-like neuroleptics (which better antagonize this effect of apomorphine than other effects such as stereotyped behavior) from haloperidol-like drugs. The latter equally antagonize the two effects of apomorphine. The effects of sulpiride are also distinct from those of chlorpromazine-like drugs which strongly antagonize stereotyped behavior, but not hypothermia induced by apomorphine. Hypothermia induced by a high dose of apomorphine (16 mg/kg) is not antagonized by neuroleptics, but is strongly antagonized by antidepressants (imipramine-like drugs, amineptine, amoxapine, nomifensine, viloxazine) and potential antidepressants (beta-adrenergic stimulants). The use of these two tests rapidly screens both antidepressants and neuroleptics and classifies neuroleptics according to their profile of action on the dopaminergic system.

Behavioral and pharmacological tests were performed on rats (males Wistar A.F.) maintained either during 6 weeks at 20 or 5 in a cage (40×40×17 cm) or during 6 weeks at 20 and during 8 days at 5 in cage.

Common effects of four beta-adrenergic blocking drugs have been investigated in mice using classical and new psychopharmacological tests. Propranolol, alprenolol, practolol and penbutolol reduced the increase in locomotor activity produced by reserpine after MAO inhibition; they produce hypothermia when associated with amphetamine and they increase oxotremorine-induced hypothermia. Regarding these three tests the studied substances ranged themseleves in the same order of potency: penbutolol greater than propranolol greater than alprenolol greater than practolol. Propranolol and penbutolol decreased the toxicity provoked in crowded mice by amphetamine or by the association pargyline-reserpine; alprenolol and practolol did not. Propranolol, penbutolol and alprenolol antagonized the amphetamine-induced increase in motor activity; practolol did not. When used at doses for which d-l propranolol was active, the dextrogyre isomer of propranolol was without effect whatever the test studied. It is suggested that for the selection of a beta-blocking drug, regarding central effects in man, the tests described would deserve consideration.

A novel test procedure for antidepressants was designed in which a mouse is suspended by the tail from a lever, the movements of the animal being recorded. The total duration of the test (6 min) can be divided into periods of agitation and immobility. Several psychotropic drugs were studied: amphetamine, amitriptyline, atropine, desipramine, mianserin, nomifensine and viloxazine. Antidepressant drugs decrease the duration of immobility, as do psychostimulants and atropine. If coupled with measurement of locomotor activity in different conditions, the test can separate the locomotor stimulant doses from antidepressant doses. Diazepam increases the duration of immobility. The main advantages of this procedure are the use of a simple, objective test situation, the concordance of the results with the validated "behavioral despair" test from Porsolt and the sensitivity to a wide range of drug doses.

Eleven benzodiazepines were evaluated in the staircase test in mice. The behavioural parameters measured were the number of steps climbed and the number of rears during a 3-min test. Climbing and to a lesser extent rears were enhanced at low doses, whereas both parameters, particularly rearing, were reduced at higher doses. The differential effects of the drugs on the two parameters were used to determine indices of anxiolytic efficacy for each drug where increases in climbing were taken to indicate the onset of anxiolytic activity and decreases in rearing the onset of sedative activity. The compounds could be ranked according to these indices in a manner which appears to reflect their therapeutic profile in man.