Emerging evidence suggests that G protein coupled receptor 55 (GPR55) may influence adrenoceptor function/activity in the cardiovascular system. Whether this reflects direct interaction (dimerization) between receptors or signalling crosstalk has not been investigated. This study explored GPR55 and alpha 1A-adrenoceptor (α1A-AR) system potential to function/signalling activities. α1A-AR mediate...

Sustained stimulation of the b -adrenoceptor leads to a desensitization of the receptor-mediated adenylyl cyclase stimulation. While 2 desensitization promoted by nanomolar concentrations of isoproterenol involves the phosphorylation of the b -adrenoceptor by protein 2 kinase A alone, both protein kinase Aand b-adrenoceptor kinase-mediated phosphorylation leading to the binding of b-arrestin co...

1. The effects of beta(3)-adrenergic stimulation were studied on the L-type Ca(2+) channel in single myocytes from rat portal vein using the whole-cell mode of the patch-clamp technique. 2. Reverse transcription-polymerase chain reaction showed that beta(1)-, beta(2)- and beta(3)-adrenoceptor subtypes were expressed in rat portal vein myocytes. Application of both propranolol (a non-selective b...

ρ-Da1a is a three-finger fold toxin from green mamba venom that is highly selective for the α1A-adrenoceptor. This toxin has atypical pharmacological properties, including incomplete inhibition of (3)H-prazosin or (125)I-HEAT binding and insurmountable antagonist action. We aimed to clarify its mode of action at the α1A-adrenoceptor. The affinity (pKi 9.26) and selectivity of ρ-Da1a for the α1A...

Clinical studies conducted with carvedilol suggest that beta-adrenoceptor antagonism is an effective therapeutic approach to the treatment of heart failure. However, many beta-adrenoceptor antagonists are weak partial agonists and possess significant intrinsic sympathomimetic activity (ISA), which may be problematic in the treatment of heart failure. In the present study, the ISAs of bucindolol...

We investigated the a,-adrenoceptor subtypes of rabbit saphenous vein which has a mixed functional population of α1 and α2 -adrenoceptors. Lateral saphenous veins were obtained from male rabbits weighing 3.20-4 kg, which were killed by overdose with pentobarbitone sodium (i.v. injection). They were easily dissected out and placed in cold, oxygenated modified Krebs-Henselite solution (Krebs)...

We investigated the relevance of selectivity for a given alpha-1-adrenoceptor subtype for in vivo uroselectivity of several alpha-1-adrenoceptor antagonists (alfuzosin, doxazosin, prazosin, tamsulosin, terazosin and 5-Me-urapidil). Comparison of the affinities of these alpha-1-adrenoceptor antagonists at the cloned alpha-1a, alpha-1b and alpha-1d-adrenoceptor subtypes revealed that tamsulosin a...

Background: Pseudopheochromocytoma is a condition that occurs more frequently than other diseases presenting with similar symptoms such as: paroxysmal hypertension, diaphoresis, pallor, palpitations. However, due to the lack of specific guidelines and awareness among physicians, it widely underdiagnosed. Conventional antihypertensive treatment ineffective in controlling which leads decreased qu...

Although noradrenaline (NA), a stress-associated neurotransmitter, seems to affect the immune system, the precise mechanisms underlying NA-mediated immunoregulation are not fully understood. We examined the effect of NA on Ag uptake (endocytosis) by dendritic cells (DCs) using murine bone marrow-derived DCs and fluorescence-labeled endocytic tracers (dextran and OVA). Ag uptake by DCs notably i...

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