title: Effect of two hemicholiniums on the disposition and distribution of endogenous free choline in anaesthetized rabbits.
abstract: 1 The effects of hemicholinium no. 3 (HC-3) and its p-terphenyl analogue (TPHC-3) on the disposition and distribution of free choline were studied in rabbits under pentobarbitone anaesthesia. Free choline was determined by bioassay. 2 The respiration of animals given 0.35 mumol/kg of HC-3 was hardly affected; however, 4 out of 6 rabbits given the same dose of TPHC-3 exhibited varying degrees of respiratory impairment. All animals that received 2 injections (1 h apart) of either HC-3 (1.4 mumol/kg) or TPHC-3 (0.7 mumol/kg) developed respiratory difficulty about 1 h after the second injection. 3 The respiratory distress was accompanied by a 2 to 15-fold rise in plasma choline concentration. This rise has been attributed to hypoxia. 4 In experiments in which choline has been infused it was observed that HC-3 could impair the animal's ability to dispose of exogenous choline. In control rabbits neither HC-3 nor TPHC-3 produced changes in plasma choline concentrations unless the respiration was depressed. 5 Either HC-3 or TPHC-3 (both at 0.35 mumol/kg) significantly (P less than 0.05) reduced the kidney choline concentration by 40% and 30% respectively; both hemicholiniums raised the lung choline concentration by about 35%. Only TPHC-3 caused a significant rise (40%) in liver choline. The choline concentrations in other tissues were unaffected by the hemicholiniums.
mesh_terms: D000818:Animals; D002794:Choline / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D006426:Hemicholinium 3 / Q000494:pharmacology*; D007263:Infusions, Parenteral; D008297:Male; D011817:Rabbits; D013997:Time Factors
chemical_list: D006426:Hemicholinium 3; D002794:Choline