Biomaterial Database

Effects of histamine on electrophysiological properties and triggered activity in guinea pig papillary muscles. 1994

X Wu, and W Q Huang, and Q Q Zhang, and Z M Yu

Department of Physiology, Nantong Medical College, P.R. China.

The effects of histamine on action potentials (APs) and on early afterdepolarizations (EADs) were studied with standard microelectrode and computer in guinea pig papillary muscles. Experiments offer evidence that histamine (6.0 mumol/l) results in a significant diminution in action potential duration at 50% repolarization (APD50) and 90% repolarization (APD90) (data taken from no abnormal automaticity and oscillatory potential cells, 10 out of 19 preparations). Particularly, histamine can induce EADs (about 58%), oscillatory potentials and triggered activity. EADs frequently occur at low stimulation rates of 0.2-1.0 Hz and with prolongation of the action potential duration. EAD-induced triggered activity may exhibit fast spontaneous APs. Cimetidine (10 mumol/l, n = 6), an H2-receptor antagonist, antagonizes the effects of histamine. In the presence of cimetidine no EADs are observed by perfusing histamine. An H1-receptor antagonist, chlorpheniramine (10 mumol/l, n = 9), has no effect on the alterations of APs induced by histamine in ventricular myocardium. The results suggest that the mechanisms of histamine-induced shortness of AP duration, EADs and triggered activity may be related to the H2 receptor-mediated enhancement of the slow inward calcium current.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008839	Microelectrodes	Electrodes with an extremely small tip, used in a voltage clamp or other apparatus to stimulate or record bioelectric potentials of single cells intracellularly or extracellularly. (Dorland, 28th ed)	Electrodes, Miniaturized,Electrode, Miniaturized,Microelectrode,Miniaturized Electrode,Miniaturized Electrodes
D009467	Neuromuscular Depolarizing Agents	Drugs that interrupt transmission at the skeletal neuromuscular junction by causing sustained depolarization of the motor end plate. These agents are primarily used as adjuvants in surgical anesthesia to cause skeletal muscle relaxation.	Depolarizing Muscle Relaxants,Muscle Relaxants, Depolarizing,Depolarizing Blockers,Agents, Neuromuscular Depolarizing,Blockers, Depolarizing,Depolarizing Agents, Neuromuscular,Relaxants, Depolarizing Muscle
D010210	Papillary Muscles	Conical muscular projections from the walls of the cardiac ventricles, attached to the cusps of the atrioventricular valves by the chordae tendineae.	Muscle, Papillary,Muscles, Papillary,Papillary Muscle
D004594	Electrophysiology	The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
D005260	Female		Females
D006168	Guinea Pigs	A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.	Cavia,Cavia porcellus,Guinea Pig,Pig, Guinea,Pigs, Guinea
D006321	Heart	The hollow, muscular organ that maintains the circulation of the blood.	Hearts
D006632	Histamine	An amine derived by enzymatic decarboxylation of HISTIDINE. It is a powerful stimulant of gastric secretion, a constrictor of bronchial smooth muscle, a vasodilator, and also a centrally acting neurotransmitter.	Ceplene,Histamine Dihydrochloride,Histamine Hydrochloride,Peremin
D006634	Histamine H1 Antagonists	Drugs that selectively bind to but do not activate histamine H1 receptors, thereby blocking the actions of endogenous histamine. Included here are the classical antihistaminics that antagonize or prevent the action of histamine mainly in immediate hypersensitivity. They act in the bronchi, capillaries, and some other smooth muscles, and are used to prevent or allay motion sickness, seasonal rhinitis, and allergic dermatitis and to induce somnolence. The effects of blocking central nervous system H1 receptors are not as well understood.	Antihistamines, Classical,Antihistaminics, Classical,Antihistaminics, H1,Histamine H1 Antagonist,Histamine H1 Receptor Antagonist,Histamine H1 Receptor Antagonists,Histamine H1 Receptor Blockaders,Antagonists, Histamine H1,Antagonists, Histamine H1 Receptor,Antihistamines, Sedating,Blockaders, Histamine H1 Receptor,First Generation H1 Antagonists,H1 Receptor Blockaders,Histamine H1 Blockers,Receptor Blockaders, H1,Antagonist, Histamine H1,Classical Antihistamines,Classical Antihistaminics,H1 Antagonist, Histamine,H1 Antagonists, Histamine,H1 Antihistaminics,Sedating Antihistamines