1 The putative direct protective effects of a series of chemically diverse xi-adrenoceptor antagonists against veratrine alkaloid-induced tetanic contractures in rat isolated left atria have been investigated. 2 Atria were mounted in organ baths containing normal, oxygenated physiological salt solution (20 ml, pH 7.4), for isometric tension recording. Atria were electrically driven at 4 Hz and ...

I The response of the P-adrenoceptors of human lymphocytes to selective agonists and antagonists has been studied quantitatively by measuring changes in cyclic adenosine-3',5'-monophosphate (cyclic AMP) levels. 2 The receptor was activated by isoprenaline and by salbutamol, and blocked by propranolol but not by practolol. A similar pattern of response was obtained with fragments of human lung t...

UNLABELLED Doxazosin, an alpha1-adrenoceptor antagonist, is used for the treatment of benign prostatic hyperplasia (BPH) and hypertension. Alpha-adrenoceptor antagonists also inhibit growth and induce apoptosis in malignant prostatic cells. The apoptotic activity is independent of their capacity to antagonize alpha-adrenoceptors. The effect of doxazosin on the growth of prostate and bladder can...

The effects of noradrenaline (Nor) and phenylephrine (Phe) on the isolated, non-precontracted perforating branch of the human internal mammary artery (HIMA) were investigated. Nor and Phe induced concentration-dependent contractions of intact and endothelium-denuded arterial rings with no statistically significant differences between the pEC(30) and maximal response values. The pretreatment of ...

Selective activation of the 5-HT1A receptor induces lower lip retraction (LLR) in rats. 8-Hydroxy-dipropylamino tetralin (8-OH-DPAT)-induced LLR could not be antagonised by the 5-HT antagonists methysergide, metergoline or mesulergine. In fact, some 5-HT antagonists induced LLR. However, 8-OH-DPAT-induced LLR could be antagonised by pindolol, spiperone, spiroxatrine and NAN-190, but not by the ...

Cholinergic and adrenergic tones were calculated for three different teleost fish species: Gadus morhua, Labrus bergylta, and Sparus aurata using atropine as a muscarinic receptor antagonist and either sotalol or propranolol as β-adrenoceptor antagonists. Depending on the order of administration of atropine and the two β-adrenoceptor antagonists, it was observed that propranolol but not sotalol...

Hypothesis / aims of study Phytotherapeutic agents, including Saw palmetto extract (SPE), are popular in many European countries as herbal remedies represent up to 80% of all drugs prescribed for benign prostatic hyperplasia (BPH) and associated lower urinary tract symptoms (LUTS). However, the mechanism of pharmacological action of SPE is not fully elucidated. Animal experiments with SPE have ...

The present study was designed to examine the specificity of (3-adrenergic antagonists for al-, 192-adrenergic and 5HT1B-serotonergic receptors by the compe titive interaction with 1251-iodocyanopindolol (1251-ICYP) as a radioligand. The 81 -adrenoceptors were preferred by acebutolol, atenolol, betaxolol, practolol, and I-, dl and d-metoprolol, while butoxamine and ICI-118,551 preferred 82-adre...