scholarly journals Effect of concanavalin a on 3H-5-hydroxytryptamine uptake in rabbit blood platelets: Interaction with adenylate cyclase activity.

1983 ◽  
Vol 33 (1) ◽  
pp. 79-84 ◽  
Author(s):  
Hiroaki NISHIO ◽  
Tomio SEGAWA
Keyword(s):  
Adenylate Cyclase ◽  
Concanavalin A ◽  
Blood Platelets ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Rabbit Blood

Some Biochemical Studies With SQ 26271: A Stable Partial Prostacyclin Agonist In The Human Platelet

1981 ◽  
Author(s):  
Don N Harris ◽  
Marie B Phillips ◽  
Inge M Michel ◽  
Harold J Goldenberg ◽  
James E Heikes ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Partial Agonist ◽  
Blood Platelets ◽  
Fold Increase ◽  
Primary Phase ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Induced Aggregation

A newly synthesized 9α-homo-9,11-epoxy-5,13-prostadienoic acid analogue, SQ 26271 (8(S)9(S)11(R)12(S)-9,11-epoxy-9α- homo-5(Z),13(E)-15(R)-hydroxyprostadienoic acid) inhibited arachidonic acid (AA)-induced platelet aggregation at concentrations which did not affect thromboxane B2 (TXB2) levels with an I50 value of 0.25 μM. It also was a potent inhibitor of platelet aggregation caused by collagen, 9,11- AzoPGH2, SQ 24810 (9,11-epoxy-9α-homo-5(Z),13(E)-15α- hydroxyprostadienoic acid) and epinephrine (secondary phase). However, it had little or no effect on thromboxane or prostaglandin synthetase activities. Moreover, SQ 26271 also inhibited the primary phase of epinephrine- and ADP- induced aggregation. In addition SQ 26271 caused a 3-fold increase in platelet adenylate cyclase activity, partially blocked prostacyclin stimulated adenylate cyclase activity and caused a 6-fold elevation of cyclic AMP levels in intact platelets, which was blocked by SQ 22536 (9-tetrahy- dro-2-furyl)adenine), an inhibitor of platelet adenylate cyclase activity. Finally, the inhibition of platelet aggregation by SQ 26271 was potentiated by an inhibitor of cyclic AMP phosphodiesterase (SQ 20009, etazolate), and reversed by SQ 22536. The above data indicate that SQ 26271 is a stable partial agonist of the prostacyclin receptor in human blood platelets.

Cytochemical Evidence for Presynatic β-Adrenergic Regulation of Secretion in the Developing Rat Submandibular Gland

1977 ◽  
Vol 35 ◽  
pp. 430-431
Author(s):  
L.S. Cutler
Keyword(s):  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Submandibular Gland ◽  
Neonatal Rat ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Parotid Glands ◽  
Adrenergic Agonist ◽  
Rat Submandibular Gland

Many studies previously have shown that the B-adrenergic agonist isoproterenol and the a-adrenergic agonist norepinephrine will stimulate secretion by the adult rat submandibular (SMG) and parotid glands. Recent data from several laboratories indicates that adrenergic agonists bind to specific receptors on the secretory cell surface and stimulate membrane associated adenylate cyclase activity which generates cyclic AMP. The production of cyclic AMP apparently initiates a cascade of events which culminates in exocytosis. During recent studies in our laboratory it was observed that the adenylate cyclase activity in plasma membrane fractions derived from the prenatal and early neonatal rat submandibular gland was retractile to stimulation by isoproterenol but was stimulated by norepinephrine. In addition, in vitro secretion studies indicated that these prenatal and neonatal glands would not secrete peroxidase in response to isoproterenol but would secrete in response to norepinephrine. In contrast to these in vitro observations, it has been shown that the injection of isoproterenol into the living newborn rat results in secretion of peroxidase by the SMG (1).

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