Effects of age and gender on rat upper airway muscle contractile properties

Upper airway muscles regulate upper airway patency. Obstructive sleep apnea is reused by upper airway collapse, and its incidence increases with age a nd is higher in men than women. The reasons for this are unknown, as little is known about the effects of age and gender on upper airway muscle. Isome tric contractile properties were determined using strips of geniohyoid and sternohyoid muscles from young and old, male and female rats in physiologic al saline solution at 30 degreesC. There were no differences between the ma le and female rats in any of the contractile properties of either muscle, a nd this was true for both young and old animals. Aging had no effect on ste rnohyoid contractile properties, but geniohyoid force was greater in old th an in young rats.