M1 and M3 muscarinic receptors mediate relaxation and contraction in canine nasal veins

Bencycloquidium bromide nasal spray is effective and safe for persistent allergic rhinitis: a phase III, multicenter, randomized, double-blinded, placebo-controlled clinical trial

PURPOSE

To investigate the efficacy and safety of bencycloquidium bromide nasal spray (BCQB) in patients with persistent allergic rhinitis (PAR).

METHODS

We enrolled 720 patients from 15 hospitals across China and randomly assigned them into BCQB group or placebo group (90 μg per nostril qid) to receive a 4-week treatment. Visual analog scale (VAS) for rhinorrhea, sneezing, nasal congestion, itching and overall symptoms were recorded by patients every day. Anterior rhinoscopy scoring was completed by doctors on every visit. Adverse events were recorded in detail.

RESULTS

A total of 354 and 351 patients were included in BCQB group and in placebo group. Baseline information was comparable. At the end of the trial, the decrease of VAS for rhinorrhea from baseline was 4.83 ± 2.35 and 2.46 ± 2.34 in BCQB group and placebo group, respectively (P < 0.001). The change ratio from baseline of VAS for rhinorrhea in BCQB group was 72.32%, higher than 31.03% in placebo group (P < 0.001). VAS for other symptoms and overall symptoms also improved significantly in the BCQB group, while no inter-group difference was found in anterior rhinoscopy scoring. The incidence of adverse reaction was similar between the two groups. Most reactions were mild and no severe reactions happened.

CONCLUSION

90 μg BCQB per nostril four times daily is effective and safe in the treatment of rhinorrhea as well as sneezing, nasal congestion and itching for patients with PAR.

RETROSPECTIVELY REGISTERED

ChiCTR2000030924, 2020/3/17.

Muscarinic-mediated vasoconstriction in human, rat and sheep umbilical cords and related vasoconstriction mechanisms

OBJECTIVE

The umbilical cord provides nutrition and oxygen to the fetus. The aim of this study was to determine the effects of acetylcholine (ACh) on umbilical cords from humans and other mammals, and the mechanisms of ACh-mediated vasoconstriction in the human umbilical cord.

DESIGN

Human and animal umbilical cords used in vascular and cellular experiments.

SETTING

Institute for Fetology, First Hospital of Soochow University, Suzhou, China.

POPULATION

A total of 85 pregnant women, 16 Sprague Dawley rats and seven pregnant sheep.

METHODS

Umbilical cord veins and arteries from humans, rats and sheep, aortas and mesenteric arteries from rats, and mesenteric, carotid and femoral arteries from ovine fetuses were used to compare vascular functions in response to ACh and to determine the mechanisms of ACh-mediated umbilical vasoconstriction. Vascular tension and ion channel currents were measured on isolated vessels and smooth muscle cells from human umbilical cords.

MAIN OUTCOME MEASURES

Provision of new evidence to conclude that ACh-stimulated vasoconstriction is common to all umbilical cords, and cellular mechanisms are linked to potassium channels.

RESULTS

ACh caused reliable vasoconstriction in umbilical veins/arteries in humans, rats and sheep, but not in any other vessels, including fetal vessels. Atropine inhibited the effects of ACh. The mRNA of ACh-muscarinic receptor subtypes M1 -M5 was expressed in human umbilical vessels. The protein kinase C antagonist GF109203X and the calcium inhibitor nifedipine decreased ACh-induced vasoconstriction in human umbilical vessels. ACh also caused a reduction in whole-cell potassium channel currents and the single-channel current of large-conductance calcium-activated potassium (BKca) channels.

CONCLUSION

Umbilical vessels are significantly different from other vessels in their response to ACh. BKca channels in smooth muscle cells may play important roles in ACh-mediated vasoconstriction in human umbilical cords. This information may be important for fetal medicine and practice with regard to the effect on fetal development of umbilical vascular functions.

Role of α2-adrenoceptors in electrical field stimulation-induced contraction of pig nasal mucosa and pharmacologic characterization of a novel α2C-adrenoceptor agonist

BACKGROUND

Blood vessels of the nasal mucosa are richly innervated by sympathetic nerves and neural mechanism is of great interest in upper respiratory tract disorders. This study was designed to determine the role of α2-adrenoceptors and, more specifically, α2C-adrenoceptors, on neurogenic sympathetic vasoconstrictor responses in pig nasal mucosa, and to define the pharmacologic profile of a novel selective α2C-adrenoreceptor agonist.

METHODS

Electrical field stimulation (EFS) was applied to nasal mucosa strips placed in an organ bath and attached to force displacement transducers for continuous recording of isometric tension. The affinity and functional activity of compound B for α2C-adrenoceptors were determined by binding analysis and the ability of compound B to stimulate [(35)S]GTPγS binding to the receptors. Compound B was also tested in a postjunctional α2C-adrenoreceptor bioassay.

RESULTS

EFS-induced contractions were partly blocked by the α2-adrenoreceptor antagonist yohimbine (41.1%) and the α2C-adrenoreceptor antagonist JP-1302 had no effect. The α2-adrenoreceptor agonist clonidine, but not compound B, exerted a significant blockade (70.6%). Compound B had high affinity (K(i) = 18 nM), produced potent agonist (EC50 = 279 nM) and good efficacy (E(max) = 73%) responses at the α2C-adrenoceptors, and displayed good functional agonist potency in the human saphenous vein α2C-adrenoreceptor bioassay (pD2 = 6.2).

CONCLUSION

(1) Neurogenic vasomotor contractility is largely regulated through an α-adrenergic mechanism; (2) pig nasal mucosa possesses post- and prejunctional α2-adrenoceptors; (3) the α2C-adrenoreceptor subtype does not seem to be involved; and (4) compound B is a novel, highly selective, and potent α2C-adrenoreceptor agonist.

A novel botulinum neurotoxin topical gel: Treatment of allergic rhinitis in rats and comparative safety profile

BACKGROUND

Rhinitis affects a significant proportion of adults and children with typically seasonal or chronic symptoms. Botulinum neurotoxin type A (BoNTA) is a well-known cholinergic antagonist widely used in a number of approved neurological and esthetic indications. This study was designed to assess the therapeutic effect of RT001, a novel topical gel formulation of BoNTA, in the treatment of allergic rhinitis using a rat model and to compare its safety profile with that of an aqueous formulation of BoNTA complex.

METHODS

A rat model of allergic rhinitis was used involving induction of classic rhinitis signs (sneezing and nasal itch) in addition to nasal inflammatory pathology to assess the degree of therapeutic effect of RT001. Comparative safety of RT001 and BoNTA complex was assessed in guinea pigs based on lethality and body weight gain.

RESULTS

Clinical signs of rhinitis were significantly (p < 0.01) relieved after a single intranasal administration of RT001 and resolved to normal baseline levels within 5 days after treatment. Mucosal inflammation characterized by edema, congestion, and vascular dilatation along with increased expression of vasoactive intestinal peptide was noted in control animals after allergy induction, whereas RT001 treatment resolved inflammation to essentially normal baseline levels. Safety studies in guinea pigs via intranasal dosing revealed ∼31-fold greater safety factor for RT001 when compared with BoNTA complex.

CONCLUSION

These results suggest that topical intranasal application of RT001 is effective in relief of clinical signs and inflammatory pathology associated with allergic rhinitis in a rodent model and may provide a safe treatment for rhinitis.