title: Increased methylation of chloroform extractable products in brain membrane preparations after propranolol injection to the rat.
abstract: 1. One and four hours after acute or chronic (8 days) intraperitoneal injection of propranolol to rat at doses up to 25 mg/kg, a beta-adrenergic receptor blockage occurred in brain homogenates, as monitored by [3H]dihydroalprenolol binding. 2. A dose-dependent increased methylation of chloroform extractable products was observed (acute treatment: 18% increase, chronic treatment: 136% increase for the dose of 25 mg/kg). 3. The implication of beta-adrenergic receptors in this effect was studied and this revealed that: (a) acute intraperitoneal injection of the less active propranolol stereoisomer (+) did not produce any effect; (b) the chronic intraperitoneal injection of salbutamol, a beta-adrenergic receptor agonist, induced a decreased methylation of chloroform extractable products (62% decrease for the dose of 2.5 mg/kg). 4. It is concluded that injection of beta-adrenergic antagonist to the rat increases basal methyltransferase activity in the brain. This induces a decreased sensitivity of the enzyme activity to noradrenaline.
authors: Unité INSERM 205, Institut National des Sciences Appliquées, Villeurbanne, France.
authors: C
authors: C
authors: Benistant
authors: C
authors: C
authors: Rey
authors: P
authors: P
authors: Fonlupt
mesh_terms: D000420:Albuterol / Q000494:pharmacology; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D002725:Chloroform; D004082:Dihydroalprenolol; D066298:In Vitro Techniques; D008297:Male; D008566:Membranes / Q000187:drug effects / Q000378:metabolism; D008745:Methylation; D009638:Norepinephrine / Q000494:pharmacology; D011433:Propranolol / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011943:Receptors, Adrenergic, beta / Q000187:drug effects; D013237:Stereoisomerism; D014020:Tissue Extracts / Q000378:metabolism*
chemical_list: D011943:Receptors, Adrenergic, beta; D014020:Tissue Extracts; D004082:Dihydroalprenolol; D002725:Chloroform; D011433:Propranolol; D000420:Albuterol; D009638:Norepinephrine