Biomaterial Database

Effects of ATP-sensitive K+ channel openers on pacemaker activity in isolated single rabbit sino-atrial node cells. 1993

H Satoh

Department of Pharmacology, Nara Medical University, Japan.

Electrophysiologic effects of ATP-sensitive K+ channel openers (cromakalim, pinacidil, and nicorandil) in single rabbit sino-atrial (SA) node cells were examined by a whole-cell voltage- and current-clamp technique. Cromakalim (> 30 microM), pinacidil (> 1 microM), and nicorandil (> 500 microM) caused a negative chronotropic effect. At low concentrations, the maximum diastolic potential was hyperpolarized and the maximum rate of depolarization was enhanced, but at high concentrations, both were reversed and action potential amplitude (APA) was decreased significantly. Pinacidil (> 30 microM) and nicorandil (> 3 microM) prolonged AP duration (APD), but cromakalim did not affect it. In whole-cell voltage-clamp experiments, cromakalim (100 microM), pinacidil (> 30 microM), and nicorandil (> 300 microM) inhibited the Ca2+ current significantly but had little or no effect on the delayed rectifying K+ current and the hyperpolarization-activated inward current. Glibenclamide (1 microM) did not antagonize the effects of K+ channel openers on Ca2+ current and APs. These results indicate that the K+ channel openers have direct inhibitory actions on spontaneous APs and Ca2+ current in rabbit SA node cells (but K+ current was unaffected), resulting in decreased pacemaker activity.

UI	MeSH Term	Description	Entries
D009536	Niacinamide	An important compound functioning as a component of the coenzyme NAD. Its primary significance is in the prevention and/or cure of blacktongue and PELLAGRA. Most animals cannot manufacture this compound in amounts sufficient to prevent nutritional deficiency and it therefore must be supplemented through dietary intake.	Nicotinamide,Vitamin B 3,Vitamin PP,3-Pyridinecarboxamide,Enduramide,Nicobion,Nicotinsäureamid Jenapharm,Papulex,Vitamin B3,3 Pyridinecarboxamide,B 3, Vitamin,B3, Vitamin,Jenapharm, Nicotinsäureamid
D011758	Pyrroles	Azoles of one NITROGEN and two double bonds that have aromatic chemical properties.	Pyrrole
D011817	Rabbits	A burrowing plant-eating mammal with hind limbs that are longer than its fore limbs. It belongs to the family Leporidae of the order Lagomorpha, and in contrast to hares, possesses 22 instead of 24 pairs of chromosomes.	Belgian Hare,New Zealand Rabbit,New Zealand Rabbits,New Zealand White Rabbit,Rabbit,Rabbit, Domestic,Chinchilla Rabbits,NZW Rabbits,New Zealand White Rabbits,Oryctolagus cuniculus,Chinchilla Rabbit,Domestic Rabbit,Domestic Rabbits,Hare, Belgian,NZW Rabbit,Rabbit, Chinchilla,Rabbit, NZW,Rabbit, New Zealand,Rabbits, Chinchilla,Rabbits, Domestic,Rabbits, NZW,Rabbits, New Zealand,Zealand Rabbit, New,Zealand Rabbits, New,cuniculus, Oryctolagus
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.
D005905	Glyburide	An antidiabetic sulfonylurea derivative with actions like those of chlorpropamide	Glibenclamide,Daonil,Diabeta,Euglucon 5,Euglucon N,Glybenclamide,HB-419,HB-420,Maninil,Micronase,Neogluconin,HB 419,HB 420,HB419,HB420
D006146	Guanidines	A family of iminourea derivatives. The parent compound has been isolated from mushrooms, corn germ, rice hulls, mussels, earthworms, and turnip juice. Derivatives may have antiviral and antifungal properties.
D006339	Heart Rate	The number of times the HEART VENTRICLES contract per unit of time, usually per minute.	Cardiac Rate,Chronotropism, Cardiac,Heart Rate Control,Heartbeat,Pulse Rate,Cardiac Chronotropy,Cardiac Chronotropism,Cardiac Rates,Chronotropy, Cardiac,Control, Heart Rate,Heart Rates,Heartbeats,Pulse Rates,Rate Control, Heart,Rate, Cardiac,Rate, Heart,Rate, Pulse
D000200	Action Potentials	Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.	Spike Potentials,Nerve Impulses,Action Potential,Impulse, Nerve,Impulses, Nerve,Nerve Impulse,Potential, Action,Potential, Spike,Potentials, Action,Potentials, Spike,Spike Potential
D000255	Adenosine Triphosphate	An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.	ATP,Adenosine Triphosphate, Calcium Salt,Adenosine Triphosphate, Chromium Salt,Adenosine Triphosphate, Magnesium Salt,Adenosine Triphosphate, Manganese Salt,Adenylpyrophosphate,CaATP,CrATP,Manganese Adenosine Triphosphate,MgATP,MnATP,ATP-MgCl2,Adenosine Triphosphate, Chromium Ammonium Salt,Adenosine Triphosphate, Magnesium Chloride,Atriphos,Chromium Adenosine Triphosphate,Cr(H2O)4 ATP,Magnesium Adenosine Triphosphate,Striadyne,ATP MgCl2
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia