cis(-)-2,3-Dihydro-3-(4-methylpiperazinylmethyl)-2-phenyl-1,5- benzothiazepin-4(5H)-one monohydrochloride and its butylbromide as M1-receptor antagonists

Effects of ubiquinol with fluid resuscitation following haemorrhagic shock on rat lungs, diaphragm, heart and kidneys

Haemorrhagic shock (HS) and fluid resuscitation can lead to increased reactive oxygen species (ROS), contributing to ischaemia-reperfusion injury and organ damage. Ubiquinol is a potent antioxidant that decreases ROS. This study examined the effects of ubiquinol administered with fluid resuscitation following controlled HS. Adult male Sprague-Dawley rats were randomly assigned to treatment [ubiquinol, 1 mg (100 g body weight)(-1)] or control groups. Rats were subjected to 60 min of HS by removing 40% of the total blood volume to a mean arterial pressure ∼45-55 mmHg. The animals were resuscitated with blood and lactated Ringer solution, with or without ubiquinol, and monitored for 120 min. At the end of the experiments, the rats were killed and the lungs, diaphragm, heart and kidneys harvested. Leucocytes were analysed for mitochondrial superoxide at baseline, end of shock and 120 min following fluid resuscitation using MitoSOX Red. Diaphragms were examined for hydrogen peroxide using dihydrofluorescein diacetate and confocal microscopy. The apoptosis in lungs, diaphragm, heart and kidneys was measured using fluorescence microscopy with acridine orange and ethidium bromide. Leucocyte mitochondrial superoxide levels were significantly lower in rats that received ubiquinol than in the control animals. Production of hydrogen peroxide and apoptosis were significantly reduced in the organs of rats treated with ubiquinol. These findings suggest that ubiquinol, administered with fluid resuscitation after HS, attenuates ROS production and apoptosis. Thus, ubiquinol is a potent antioxidant that may be used as a potential treatment to reduce organ injury following haemorrhagic events.

In vitro and in vivo antimuscarinic effects of (-)cis 2,3-dihydro-3-(4-methylpiperazinylmethyl)-2-phenyl-1,5 benzothiazepin-4-(5H)one HCl (BTM-1086) in guinea pig peripheral tissues

The potency and selectivity of (-)cis-2,3-dihydro-3-(4-methylpiperazinylmethyl)-2-phenyl-1,5 benzothiazepin-4-(5H)one HCl (BTM-1086) for muscarinic receptor subtypes was compared in functional assay systems, in guinea pig peripheral tissues, to known reference drugs: atropine (nonselective), pirenzepine (M1), AF-DX 116 (M2) and HHSiD (M3). Like atropine, BTM-1086 was a potent, nonselective, competitive muscarinic antagonist with no detectable antispasmodic activity in urinary bladder or ileal muscle. In vivo, in the guinea pig cystometrogram, BTM-1086 depressed intravesical bladder pressure (PvesP) with the same efficacy and potency as oxybutynin, a drug used clinically for the treatment of urinary incontinence. The pharmacological profile of BTM-1086, however, suggests that it may not be suitable for development for bladder dysfunction disorders.

Affinity profiles of BTM-1086 and BTM-1041 at muscarinic receptor subtypes and at H1- and alpha 1-receptors

The affinities of the (+) and (-) enantiomers of the antimuscarinic benzothiazepinone derivative, cis-2,3-dihydro-3-(4-methyl-1-piperazinylmethyl)-2-phenyl-1,5-benzoth iazepin-4 (5H)-one (BTM-1041 and BTM-1086), for muscarinic receptor subtypes, histamine H1-receptors and alpha 1-adrenoceptors were determined in vitro using isolated organs: field-stimulated rabbit vas deferens (M1-receptors), guinea-pig left atrium (M2-receptors), guinea-pig ileum (M3- and histamine H1-receptors) and rat vas deferens (alpha 1-adrenoceptors). We also assessed the binding profile of BTM-1041 and BTM-1086 at muscarinic receptor subtypes in guinea-pig cortex (M1), heart (M2) and salivary glands (M3) as well as at alpha 1-adrenoceptors in rat cerebral cortex. Functional and binding experiments showed that the (-) enantiomer (BTM-1086) had a high affinity (pA2 = 7.98-8.81; pKi = 8.31-9.15) for the three muscarinic receptor subtypes, whereas the (+) enantiomer (BTM-1041) showed a low antimuscarinic potency (pA2 = 4.87-5.31; pKi = 4.85-5.55). This results in an extremely high stereoselectivity for these optical isomers [-)/(+) ratios = 1023 to 6918). The affinity of the (-) enantiomer BTM-1086 was lower for both histamine H1- and alpha 1-receptors than for muscarinic receptors, whereas the reverse was true for the (+) enantiomer, BTM-1041. Thus, the stereochemical demands for the two optical isomers were most stringent at muscarinic receptors but were inverse and less pronounced at histamine H1- and alpha 1-receptors (stereoselectivity ratios = 0.16-0.22).