Biomaterial Database

Properties of the inotropic response in rat papillary muscles to the dihydropyridine "Ca-channel activator" BAY K 8644. 1988

T Skomedal, and I Schiander, and H Aass, and J B Osnes

Department of Pharmacology, University of Oslo, Norway.

The aim of the present study was 1) to characterize qualitatively the positive inotropic effect of the Ca-channel activator BAY K 8644 and to compare this response to response-types with known and different relationship to the cyclic AMP (cAMP) system (e.g. responses elicited through alpha- and beta-adrenergic receptor stimulation) and 2) to study the effect of simultaneous muscarinic cholinergic stimulation upon the BAY K 8644 response in order to further evaluate the role of the cAMP system in this response. The responses were evaluated in isolated, electrically paced, isometrically contracting papillary muscles from rat heart. Isometric tension (Tmax), rate of rise and decline of tension (first derivative = T') and rate of transition from tension rise to tension decline (negative part of second derivative = T") were recorded. In the presence of the alpha 1-adrenergic receptor blocker prazosin (10(-7) mol/l) and the beta-adrenergic receptor blocker timolol (10(-6) mol/l), the positive inotropic effect of 1.7 x 10(-6) mol/l BAY K 8644 developed rather slowly with a time to half maximal effect of about 4 minutes. Qualitatively the response was characterized by an almost proportional ("symmetrical") increase in all parts of the contraction-relaxation cycle with a small prolongation of time to peak tension and of the duration of the whole cycle. This response contrasted sharply with the cAMP-dependent response to beta-receptor stimulation (beta-type response with shortening of time to peak tension), but was very similar to the cAMP-independent response to alpha-receptor stimulation (alpha-type response).(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008297	Male		Males
D009200	Myocardial Contraction	Contractile activity of the MYOCARDIUM.	Heart Contractility,Inotropism, Cardiac,Cardiac Inotropism,Cardiac Inotropisms,Contractilities, Heart,Contractility, Heart,Contraction, Myocardial,Contractions, Myocardial,Heart Contractilities,Inotropisms, Cardiac,Myocardial Contractions
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
D011224	Prazosin	A selective adrenergic alpha-1 antagonist used in the treatment of HEART FAILURE; HYPERTENSION; PHEOCHROMOCYTOMA; RAYNAUD DISEASE; PROSTATIC HYPERTROPHY; and URINARY RETENTION.	Furazosin,Minipress,Pratsiol,Prazosin HCL,Prazosin Hydrochloride,HCL, Prazosin,Hydrochloride, Prazosin
D011919	Rats, Inbred Strains	Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.	August Rats,Inbred Rat Strains,Inbred Strain of Rat,Inbred Strain of Rats,Inbred Strains of Rats,Rat, Inbred Strain,August Rat,Inbred Rat Strain,Inbred Strain Rat,Inbred Strain Rats,Inbred Strains Rat,Inbred Strains Rats,Rat Inbred Strain,Rat Inbred Strains,Rat Strain, Inbred,Rat Strains, Inbred,Rat, August,Rat, Inbred Strains,Rats Inbred Strain,Rats Inbred Strains,Rats, August,Rats, Inbred Strain,Strain Rat, Inbred,Strain Rats, Inbred,Strain, Inbred Rat,Strains, Inbred Rat
D002217	Carbachol	A slowly hydrolyzed CHOLINERGIC AGONIST that acts at both MUSCARINIC RECEPTORS and NICOTINIC RECEPTORS.	Carbamylcholine,Carbacholine,Carbamann,Carbamoylcholine,Carbastat,Carbocholine,Carboptic,Doryl,Isopto Carbachol,Jestryl,Miostat,Carbachol, Isopto
D000242	Cyclic AMP	An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.	Adenosine Cyclic 3',5'-Monophosphate,Adenosine Cyclic 3,5 Monophosphate,Adenosine Cyclic Monophosphate,Adenosine Cyclic-3',5'-Monophosphate,Cyclic AMP, (R)-Isomer,Cyclic AMP, Disodium Salt,Cyclic AMP, Monoammonium Salt,Cyclic AMP, Monopotassium Salt,Cyclic AMP, Monosodium Salt,Cyclic AMP, Sodium Salt,3',5'-Monophosphate, Adenosine Cyclic,AMP, Cyclic,Adenosine Cyclic 3',5' Monophosphate,Cyclic 3',5'-Monophosphate, Adenosine,Cyclic Monophosphate, Adenosine,Cyclic-3',5'-Monophosphate, Adenosine,Monophosphate, Adenosine Cyclic
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
D001498	3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester	A dihydropyridine derivative, which, in contrast to NIFEDIPINE, functions as a calcium channel agonist. The compound facilitates Ca2+ influx through partially activated voltage-dependent Ca2+ channels, thereby causing vasoconstrictor and positive inotropic effects. It is used primarily as a research tool.	BK-8644,Bay R5417,Bay-K-8644,Bay-K-8644, (+)-Isomer,Bay-K-8644, (+-)-Isomer,Bay-K-8644, (-)-Isomer,Bay-K8644,Bay-R-5417,BK 8644,BK8644,Bay K 8644,Bay K8644,Bay R 5417,BayK8644,BayR5417,R5417, Bay