title: Evidence of beta-adrenergic involvement in forced swimming-induced behavioural despair of mice.
abstract: Modulation of forced swimming-induced immobility by beta-adrenoceptor activation was investigated in mice. Isoprenaline prolonged the immobility duration of mice in a dose-related manner when the animals were forced to swim for 6 min periods. On the other hand, salbutamol (a beta 2-agonist) reduced the immobility duration of mice. Pretreatment with propranolol (1,2,4,8 and 16 mg/kg, ip), atenolol (10 mg/kg, ip) and metoprolol (10 mg/kg, ip) antagonized the immobility-enhancing effect of isoprenaline. Chronic administration (10 mg/kg/day) for 8 days of propranolol and imipramine protected the animals from isoprenaline-evoked prolongation of immobility. These findings suggest that central beta 1- and beta 2-subtypes of adrenoceptors may be acting in opposite directions to modify the immobility duration of mice. Activation of central beta 1-adrenoceptors may lead to enhanced behavioural despair, whereas a reverse effect may be observed on beta 2-adrenoceptor activation.
mesh_terms: D000818:Animals; D001262:Atenolol / Q000494:pharmacology; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology*; D005260:Female; D007099:Imipramine / Q000494:pharmacology; D007103:Immobilization; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D008790:Metoprolol / Q000494:pharmacology; D051379:Mice; D005082:Physical Exertion; D011433:Propranolol / Q000494:pharmacology; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism*; D012110:Reserpine / Q000494:pharmacology; D013315:Stress, Psychological / Q000378:metabolism*; D013550:Swimming
chemical_list: D011943:Receptors, Adrenergic, beta; D001262:Atenolol; D012110:Reserpine; D011433:Propranolol; D008790:Metoprolol; D007545:Isoproterenol; D007099:Imipramine