Impacts of Opioids on Respiratory Drive During Sleep

Inclusion Criteria: * Healthy controls: Apnea Hypopnea Index (AHI) \< 5 events/hr on in-laboratory PSG within 3 months of enrollment * OSA group: AHI \> 10 events/hr on in-laboratory PSG within 3 months of enrollment; treated or untreated. Exclusion Criteria: * Sleep disordered breathing or respiratory disorders (other than OSA in the OSA group), such as central sleep apnea (\>50% of respiratory events scored as central), chronic hypoventilation/hypoxemia (awake SaO2 \< 92% by oximetry) due to chronic obstructive pulmonary disease or other respiratory conditions. * Other sleep disorders: periodic limb movements (periodic limb movement index \> 20/hr), narcolepsy, or parasomnias. * Any unstable major medical condition. * Medications expected to stimulate or depress respiration (including other opioids taken at home, barbiturates, benzodiazepines, doxapram, almitrine, theophylline, 4-hydroxybutanoic acid). * History of allergy to lidocaine or oxymetazoline. * Contraindications for morphine, including: * allergy to morphine or opioids * chronic obstructive pulmonary disease, asthma, or other significant respiratory disorders * kidney or liver dysfunction, as this can affect the metabolism and excretion of morphine, leading to increased risk of toxicity. * women who are pregnant or breastfeeding will be excluded due to potential risks to the fetus or infant. * history of substance abuse, particularly opioid abuse, will be excluded to prevent potential misuse or relapse. * current use of central nervous system depressants. * individuals with gastrointestinal obstruction. Constipation is not an exclusion criterion because morphine is only administered for one night. * recent head injury, brain tumors, or other conditions leading to increased intracranial pressure. * unstable heart disease, particularly those with risk factors for or a history of heart rhythm disorders. * epilepsy or a history of seizures, as morphine can lower the seizure threshold. * severe psychiatric conditions, particularly those with a history of psychosis, as opioids can exacerbate these conditions. * medications that interact with morphine, such as selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), Monoamine oxidase inhibitors (MAOIs), and the atypical antidepressants buproprion and trazodone. * untreated or unstable endocrine disorders like adrenal insufficiency or thyroid dysfunction.