Serotonin depletion increases respiratory variability in freely moving rats: implications for panic disorder.
To elucidate if serotonergic transmission affects respiratory variability, a parameter consistently found increased in patients with panic disorder, we studied the effect of a serotonin synthesis inhibitor, para-chlorophenylalanine (PCPA), on respiratory variability at baseline and during CO2-induced hyperventilation in awake and unrestrained rats. Forty male Wistar rats were given intraperitoneal injections of PCPA (300 mg/kg) or saline 72, 48 and 24 h before registration of respiration in a plethysmograph allowing the animals to move freely. PCPA-treated rats displayed significantly higher tidal volume variability and minute volume variability, both at baseline and during CO2 exposure, compared to controls. The results support the notion that serotonin dysfunction may contribute to the enhanced respiratory variability observed in patients with panic disorder.
Annerbrink
Kristina
K
Department of Pharmacology, Göteborg University, Box 431, SE 405 30 Göteborg, Sweden. kristina.annerbrink@pharm.gu.se
Olsson
Marie
M
Melchior
Lydia K
LK
Hedner
Jan
J
Eriksson
Elias
E
D000704:Analysis of Variance; D000818:Animals; D002245:Carbon Dioxide; D010134:Fenclonine / Q000494:pharmacology; D006985:Hyperventilation / Q000139:chemically induced / Q000503:physiopathology; D008297:Male; D010991:Plethysmography / Q000379:methods; D051381:Rats; D017208:Rats, Wistar; D012137:Respiratory System / Q000187:drug effects / Q000503:physiopathology*; D012701:Serotonin / Q000172:deficiency*; D012702:Serotonin Antagonists / Q000494:pharmacology; D013997:Time Factors; D014851:Wakefulness / Q000187:drug effects / Q000502:physiology
D012702:Serotonin Antagonists; D002245:Carbon Dioxide; D012701:Serotonin; D010134:Fenclonine