Serotonin-induced cortisol release in CPAP-treated obstructive sleep apnea patients.
Previously, we demonstrated elevated cortisol production/release in response to the administration of the serotonin precursor, L-5-hydroxytryptophan (L-5-HTP) in untreated patients with obstructive sleep apnea (OSA). We hypothesized that if this elevated cortisol response to L-5-HTP was related to OSA, this finding would not be present in OSA patients treated with nasal continuous positive airway pressure (nCPAP). Eleven OSA patients treated for at least 1 month with nCPAP were studied. On two different days, we measured blood cortisol level every 15 min for 4 h following the ingestion of L-5-HTP, 0.4 mg/kg, or placebo, both given with carbidopa, a peripheral tryptophan decarboxylase inhibitor, used to prevent peripheral L-5-HTP metabolism before brain absorption. For a given subject, the cortisol response was calculated as the difference between the area under the curve of the L-5-HTP and placebo responses. In the nCPAP-treated OSA patients, this net cortisol response, 577 +/- 240 min.micrograms/dL, was less than the value found in the previously studied untreated OSA group, 1,198 +/- 227 min.micrograms/dL (p < 0.05) and not different from the previously studied nonapneic control group, 469 +/- 154 min.micrograms/dL. From these results, we speculate that nCPAP treatment reverses the elevated cortisol response to serotonergic stimulation seen in untreated OSA patients.
Hudgel
D W
DW
Department of Medicine, MetroHealth Medical Center, Cleveland, OH 44109-1998, USA.
Gordon
E A
EA
D006916:5-Hydroxytryptophan / Q000494:pharmacology; D000328:Adult; D065105:Aromatic Amino Acid Decarboxylase Inhibitors; D002230:Carbidopa / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011175:Positive-Pressure Respiration; D011863:Radioimmunoassay; D012701:Serotonin / Q000502:physiology*; D012891:Sleep Apnea Syndromes / Q000097:blood* / Q000628:therapy
D065105:Aromatic Amino Acid Decarboxylase Inhibitors; D004791:Enzyme Inhibitors; D012701:Serotonin; D006916:5-Hydroxytryptophan; D002230:Carbidopa; D006854:Hydrocortisone