scholarly journals COMPARISON OF NEWLY SYNTHESIZED β-ADRENERGIC BLOCKERS, OPC 1085 AND SQ 11725, WITH PINDOLOL AND PROPRANOLOL IN THE BLOOD-PERFUSED CANINE SA NODE AND PAPILLARY MUSCLE PREPARATIONS

1976 ◽  
Vol 26 (4) ◽  
pp. 504-506 ◽  
Author(s):  
Koroku HASHIMOTO ◽  
Tomohiko KIMURA ◽  
Yoichi YABUUCHI
Keyword(s):  
Papillary Muscle ◽  
Sa Node ◽  
Adrenergic Blockers

CATECHOLAMINE ANTAGONISM TO OXYTOCIN-INDUCED MILK-EJECTION

1971 ◽  
Vol 68 (1_Suppla) ◽  
pp. S5-S38 ◽  
Author(s):  
Helmuth Vorherr
Keyword(s):  
Receptor Blockade ◽  
Milk Ejection ◽  
Beta Adrenergic ◽  
Beta Receptor ◽  
Beta Receptors ◽  
Alpha Receptors ◽  
Adrenergic Blockers ◽  
Beta Receptor Blockade ◽  
Second Pain ◽  
Stimulation Of

ABSTRACT In lactating rats and rabbits the mode of antagonism of sympathomimetics, angiotensin or pain toward oxytocin-induced milk-ejection was investigated. In rats intra-arterial (intrafemoral) doses of 0.01–0.02 μg or intravenous (iv) doses of 0.1–0.5 μg of either epinephrine, isoproterenol, norepinephrine, angiotensin or 10 μg of phenylephrine injected simultaneously with, or 30 seconds before an oxytocin dose (10 μU intrafemoral, 300 μU iv) greatly inhibited or suppressed the oxytocin response. A 15 second pain stimulus caused moderate inhibition. With alpha-receptor blockade pain, epinephrine, isoproterenol, norepinephrine, phenylephrine and angiotensin inhibition were, respectively, 70%, 75%, 100%, 40%, 0% and 100%. Under beta-receptor blockade the corresponding values were 14%, 40%, 0%, 70%, 100% and 100%; with simultaneous intrafemoral injections neither catecholamine was inhibitory toward oxytocin. In corresponding rabbit experiments approximately 10-fold higher iv drug dosages were applied and similar results were observed. In both species, combined alpha and beta-receptor blockade nearly eliminated the antagonistic actions of sympathomimetics toward oxytocin, whereas angiotensin inhibition persisted unchanged. The results indicate: 1) Mammary myoepithelial cells contain beta-adrenergic receptors but no alpha-receptors; 2) Inhibition of oxytocin-induced milk-ejection by isoproterenol and phenylephrine is meditated through stimulation of myoepithelial beta-receptors (myoepithelial relaxation) and vascular alpha-receptors (vasoconstriction), respectively; 3) Epinephrine and norepinephrine inhibition of milk-ejection is due to stimulation of vascular alpha-receptors and myoepithelial beta-receptors; 4) Angiotensin effects are unrelated to adrenergic receptor mechanisms; 5) Administration of both alpha and beta-adrenergic blockers is desirable for stabilizing the sensitivity of the oxytocin milk-ejection assay preparation against interference from endogenous or exogenous catecholamines; 6) Other than using adrenergic blockers, pharmacologic doses of oxytocin can correct nursing difficulties in animals and man with hyperfunction of the adrenal-sympathetic system.

Pseudo-endocarditis secondary to ruptured posteromedial papillary muscle with anatomical variation: A Case Report

2020 ◽  
pp. 179
Author(s):  
Keyword(s):  
Myocardial Infarction ◽  
Mitral Valve ◽  
Papillary Muscle ◽  
Anatomical Variation ◽  
Low Grade ◽  
Papillary Muscle Rupture ◽  
Atypical Chest Pain ◽  
Anatomical Variant ◽  
Muscle Rupture ◽  
Mitral Valve Vegetation

Myocardial infarction is the leading cause of papillary muscle rupture. This complication occurs in up to 5% of cases post MI and although rare, it constitutes a cardiac emergency if left untreated. On this basis, a 59-year-old male presented with low-grade fever and atypical chest pain with raised inflammatory markers and troponin levels. He was treated for infective endocarditis after echocardiography revealed a mass on the mitral valve, which was presumed to be a mitral valve vegetation and so he completed a 6-weeks course of antibiotics followed by elective mitral valve replacement surgery. During surgery, it was discovered that there was no endocarditis. Instead an unusually small muscle head of one of the posteromedial papillary muscle groups had ruptured secondary to an inferior myocardial infarction. This ruptured muscle head was highly mobile and mimicked a mitral valve vegetation. The mitral valve was successfully repaired, and the right coronary artery grafted. He made a full recovery but developed new-onset atrial fibrillation for which he is awaiting elective cardioversion. One should have a high index of suspicion for diagnosing papillary muscle rupture as it may mimic valvular vegetation on echocardiography, especially if the papillary muscle involved is an anatomical variant.

Enhanced Regional Deformation at the Anterior Papillary Muscle Insertion Site After Chordal Transsection

Circulation ◽  
1996 ◽  
Vol 93 (3) ◽  
pp. 585-593 ◽  
Author(s):  
Yasuo Takayama ◽  
Jeffrey W. Holmes ◽  
Ian LeGrice ◽  
James W. Covell
Keyword(s):  
Papillary Muscle ◽  
Insertion Site ◽  
Regional Deformation ◽  
Muscle Insertion ◽  
Anterior Papillary Muscle

Papillary Muscle Perfusion Pattern

Circulation ◽  
1995 ◽  
Vol 91 (6) ◽  
pp. 1714-1718 ◽  
Author(s):  
Paolo Voci ◽  
Federico Bilotta ◽  
Quintilio Caretta ◽  
Corrado Mercanti ◽  
Benedetto Marino
Keyword(s):  
Papillary Muscle ◽  
Muscle Perfusion
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