Smooth muscle relaxation activity of an aqueous extract of dried immature fruit of Poncirus trifoliata (PF-W) on an isolated strip of rat ileum.

We demonstrated that an aqueous extract of dried immature fruit of Poncirus trifoliate (PF-W) produces relaxation of intestinal smooth muscle using the ileac strips of a rat. Furthermore, the underlying mechanism of its relaxant activity was investigated. PF-W was prepared using the standard extraction protocol. A 1.5 - 2 cm long rat ileac strip was placed in an organ bath with Tyrode's solution and smooth muscle contractility was recorded by connecting it to a force transducer. Various compounds were added to the organ baths, and changes in muscular contractility were measured. PF-W concentration-dependently induced relaxation of rat ileac strips that were contracted both spontaneously and via acetylcholine treatment. Various potassium channel blockers did not inhibit the relaxation by PF-W. No difference in the effect of PF-W was observed between ileac strips treated with low (20 mM) and high concentrations (60 mM) of KCl. PF-W inhibited the contraction of rat ileac strips induced by extracellular calcium. PF-W acts as a potent smooth muscle relaxant, implicating its possible action as a rapid acting reliever for abdominal pains and a cure for intestinal convulsion. Considering that PF-W also exhibits prokinetic activity, its use in various gastrointestinal disorders seems promising.

Male-specific alteration in excitatory post-synaptic development and social interaction in pre-natal valproic acid exposure model of autism spectrum disorder.

Autism spectrum disorder (ASD) is a pervasive developmental disorder characterized by three main behavioral symptoms including social deficits, impaired communication, and stereotyped and repetitive behaviors. ASD prevalence shows gender bias to male. Prenatal exposure to valproic acid (VPA), a drug used in epilepsy and bipolar disorder, induces autistic symptoms in both human and rodents. As we reported previously, prenatally VPA-exposed animals at E12 showed impairment in social behavior without any overt reproductive toxicity. Social interactions were not significantly different between male and female rats in control condition. However, VPA-exposed male offspring showed significantly impaired social interaction while female offspring showed only marginal deficits in social interaction. Similar male inclination was observed in hyperactivity behavior induced by VPA. In addition to the ASD-like behavioral phenotype, prenatally VPA-exposed rat offspring shows crooked tail phenotype, which was not different between male and female groups. Both male and female rat showed reduced GABAergic neuronal marker GAD and increased glutamatergic neuronal marker vGluT1 expression. Interestingly, despite of the similar increased expression of vGluT1, post-synaptic marker proteins such as PSD-95 and α-CAMKII expression was significantly elevated only in male offspring. Electron microscopy showed increased number of post-synapse in male but not in female at 4 weeks of age. These results might suggest that the altered glutamatergic neuronal differentiation leads to deranged post-synaptic maturation only in male offspring prenatally exposed to VPA. Consistent with the increased post-synaptic compartment, VPA-exposed male rats showed higher sensitivity to electric shock than VPA-exposed female rats. These results suggest that prenatally VPA-exposed rats show the male preponderance of ASD-like behaviors including defective social interaction similar to human autistic patients, which might be caused by ectopic increase in glutamatergic synapses in male rats.

Convulsion-related activities of Scutellaria flavones are related to the 5,7-dihydroxyl structures.

We screened the major bioactive flavones isolated from Scutellaria baicalensis (baicalin, baicalein and oroxylin A) for their convulsion related activities. In electrogenic response score system and the pentylenetetrazole seizure model, baicalein but not oroxylin A and baicalin exhibited anticonvulsant effects. In vitro studies also revealed that baicalein induced intracellular Cl(-) influx, whereas oroxylin A blocked muscimol- and baicalein-induced intracellular Cl(-) influx. The anticonvulsant effect of baicalein was inhibited by flumazenil, a benzodiazepine(BZD) receptor antagonist. Therefore, anticonvulsive effect of baicalein was mediated by the BZD binding site of GABA(A) receptor. The 5, 7-dihydroxyl group is present in the structure of the three flavones. It is postulated that this group played a key role in inducing convulsion-related activities.

Bladder-relaxant properties of the novel benzofuroindole analogue LDD175.

The present study describes the bladder-relaxant properties of LDD175 (4-chloro-7-trifluoromethyl-10H-benzo[4,5]furo [3,2-b]indole-1-carboxylic acid), a novel benzofuroindole compound. LDD175 had no significant effect on the spontaneous and electrically evoked bladder contractions, but produced concentration-dependent relaxation in strips precontracted by 1 micromol/l acetylcholine (pEC(50) = 5.9 +/- 0.2, E(max) = 90.3 +/- 2.6%; 100 micromol/l, n = 6). In high K(+)- (20 and 80 mmol/l) stimulated samples, LDD175 caused a concentration-dependent relaxant activity which was significant in 20 mmol/l K(+) (pEC(50) = 5.6 +/- 0.2, E(max) = 63.1 +/- 4.8%, n = 6), but not in 80 mmol/l K(+) (pEC(50) = 5.1 +/- 0.3, E(max) = 12.7 +/- 2.5%, n = 6). Iberiotoxin (100 nmol/l), a specific BKCa blocker, attenuated the compound's relaxative effect (vehicle = 65.7 +/- 9.2% vs. iberiotoxin 28.0 +/- 3.5%, respectively, n = 3), but not tetraethylammonium chloride (10 mmol/l), a nonselective K(+) channel blocker, barium chloride (10 mmol/l), a conventional K(IR) blocker, and glibenclamide (1 mmol/l), a K(ATP) blocker. LDD175 was evaluated in both endothelium-intact and denuded rat aorta contracted with high K(+). In these preparations, LDD175 did not produce significant inhibition. Administered intravenously to conscious restrained rats, LDD175 (10 mg/kg) did not alter the rat's hemodynamic activity (i.e. blood pressure and heart rate). When tested in the spontaneously hypertensive rats (SHR) for its influence on their voiding behavior, LDD175 (5 and 10 mg/kg) significantly reduced voiding frequency and lengthened void intervals of the animals. These observations: (1) reveal the BKCa channel potentiation of LDD175; (2) support previous claims concerning the bladder (vs. vascular) selectivity of benzofuroindole compounds; (3) demonstrate the efficacy of LDD175 in the animal model of bladder overactivity (SHR). Therefore, the compound may be potentially useful in the treatment of bladder overactivity.

Inhibition of intestinal motility by the putative BK(Ca) channel opener LDD175.

LDD175 (4-chloro-7-trifluoromethyl-10H-benzo[4,5]furo[3,2-b]indole-1-carboxylic acid) is a benzofuroindole compound characterized previously as a potent opener of the large conductance calcium activated (BK(Ca)) channels. Activators of the BK(Ca) channels are potential therapies for smooth muscle hyperactivity disorders. The present study investigates the influence of LDD175 on the mechanical activity of the ileum smooth muscle. LDD175 inhibited spontaneous contractions of the ileum in a concentration-dependent manner (pEC(50)=5.9 +/- 0.1) (E (max)=96 +/- 1.0% at 100 muM, n=3). It also remarkably inhibited contractions due to acetylcholine (ACh) (pEC(50)=5.3 +/- 0.1)(E (max)=97.7 +/- 2.3%, n=6) and electrical field stimulation (EFS) (pEC(50)=5.5 +/- 0.1) (E (max)=83.3 +/- 6.0%, n=6). In strips precontracted by 20 mM KCl, LDD175 significantly reduced the contractions yielding a pEC(50) of 6.1 +/- 0.1 and E (max) of 96.6 +/- 0.9%, (n=6). In 60 mM KCl, a concentration-dependent inhibition was observed with respective pEC(50) and E (max) values of 4.1 +/- 0.1 and 50.8 +/- 5.0% (n=3). BK(Ca) channel blockers iberiotoxin (IbTX) and tetraethylammonium chloride (TEA, 1 mM) attenuated the relaxative effect of LDD175 but not barium chloride (BaCl(2)), and glibenclamide (K(IR) and K(ATP) channel blockers, respectively). These data demonstrate the antispasmodic activity of LDD175 attributable to the potentiation of the BK(Ca) channels.