The influence of a transmucosal cholinergic agonist on pharyngeal muscle activity

Turning Over a New Leaf-Pharmacologic Therapy in Obstructive Sleep Apnea

Despite extensive research, there is currently no approved drug for obstructive sleep apnea (OSA) treatment. OSA is a heterogeneous condition that involves multiple dominating pathophysiological traits. Drug development in this field needs to address both pathophysiological mechanisms and associated comorbid conditions in order to meet requirements for long-term therapy in OSA. Several drug candidates have been proposed and ongoing phase II trials that target various forms of sleep-disordered breathing have been initiated. The field is moving toward tailored therapeutic approaches in patients with OSA.

A neurotoxinological approach to the treatment of obstructive sleep apnoea

Current treatment approaches to the problem of obstructive sleep apnoea (OSA) have limitations. Specifically, invasive anatomical-based surgery and dental appliances typically do not alleviate obstruction at an acceptable rate, and compliance to continuous positive airway pressure (CPAP) devices is frequently suboptimal. Neurotoxinological treatment approaches are widespread in the field of medicine, but as yet have not been evaluated as a treatment for sleep-disordered breathing. In this review, it is argued that despite widespread recognition of the loss of upper airway (UA) muscular tone and/or reflexes in the expression of OSA, most treatment interventions to date have focused on anatomical principles alone. Several hypothesised neurotoxinological interventions aimed at either enhancing UA neuromuscular tone and/or reflexes are proposed, and some preliminary data is presented. Although in its early infancy, with considerable toxicity studies in animals yet to be done, a neurotoxinological approach to the problem of OSA holds promise as a future treatment, with the potential for both high effectiveness and patient compliance.

Effects of nicotine on rat sternohyoid muscle contractile properties

Obstructive sleep apnoea (OSA) is a major clinical disorder characterised by recurring episodes of pharyngeal collapse during sleep. At present, there remains no satisfactory treatment for OSA. Pharmacological therapies as a potential treatment for the disorder are an attractive option and include agents that increase the contractility of the pharyngeal muscles. The aim of the present study was to examine the effects of nicotine on upper airway muscle contractile properties. In vitro isometric contractile properties were determined using strips of rat sternohyoid muscle in physiological salt solution containing nicotine (0-100 microg/ml) at 25 degrees C. Isometric twitch and tetanic tension, contraction time, half-relaxation time and tension-frequency relationship were determined by electrical field stimulation with platinum electrodes. Fatigue was induced by stimulation at 40 Hz with 300 ms trains at a frequency of 0.5 Hz for 5 min. Nicotine at a concentration of 1 microg/ml was associated with a significant increase in sternohyoid muscle specific tension compared to control data. Dose-dependent increases in contractile tension were not observed. Nicotine had effects on tension-frequency relationship and endurance properties of the sternohyoid muscle at some but not all doses. A leftward shift in the tension-frequency relationship was observed at low stimulus frequencies (20-30 Hz) for nicotine at a concentration of 1 and 5 microg/ml and a significant increase in fatigue resistance was observed with nicotine at a concentration of 10 microg/ml. As fatigue of the upper airway muscles has been implicated in obstructive airway conditions, a pharmacological agent that improves muscle endurance may prove useful as a potential treatment for such disorders. Therefore, further studies of the effects of nicotinic agonists on upper airway function are warranted.

Clinical effects of locally delivered nicotine in obstructive sleep apnea syndrome

Obstructive sleep apnea (OSA) is a common disorder characterized by disordered breathing and associated with increased mortality and cardiovascular morbidity. A factor in the pathogenesis of OSA is hypotonia of the upper airway muscles during sleep, resulting in occlusion of the upper airway. Nicotine may be a suitable drug because it is a stimulant of breathing and activity of oropharyngeal muscles. A novel delivery system, a nicotine tooth patch (NTP) that releases nicotine continuously, has been developed by Perio Products (Jerusalem, Israel). A 2-mg NTP achieved low plasma levels of nicotine with high saliva levels (62 microg/mL), presumably resulting in high nicotine levels in the oropharynx. The aim of this study was to evaluate the effect of two doses of NTP, 2 mg and 4 mg, on the clinical features in OSA. Ten subjects with OSA were admitted overnight and monitored by polysomnography at baseline and during two treatments. The treatments were blind and in a randomized order. After a 4.3-mg NTP, T(max) was 40 +/- 16 minutes, C(max) was 123 +/- 43 microg/mL, and terminal T(1/2) was 29 +/- 11 minutes in saliva. Substantial nicotine levels persisted in saliva for approximately 4 hours. There was no effect of nicotine on the apnea-hypopnea index, even during the first 4 hours when there were high levels of nicotine in saliva (26.4 +/- 11.6, 26.8 +/- 19.5, and 26.8 +/- 23), or on sleep stages. Eppworth Sleepiness Scale scores were lower with a 4.3-mg NTP (9.1 +/- 4.5, 9.1 +/- 7.7, and 5.9 +/- 6.5). Locally delivered nicotine at the doses used had no significant effect on OSA.