Age-dependent changes in serotonergic modulation of yawning in the rat.
Serotonin (5-HT) effects on physostigmine (PHY)-induced yawning were studied in LY Sprague-Dawley rats by injecting Lu 10 171 (citalopram), a specific 5-HT uptake blocker, and two antagonists--methiothepine and ritanserin--which differ slightly in the selectivity of their actions on different 5-HT receptor subtypes. Infant and young rats show significant increases in PHY-induced yawning when preinjected with citalopram (5-10 mg/kg). Two-month-old animals show this effect only with 10 mg/kg. With adult animals (3-5 months old), the effect is the opposite: Yawning decreases. The facilitory effect in infant and young rats was counteracted by methiothepine but not by ritanserin, suggesting that it is mediated through 5-HT1A or 5-HT1B receptor subtypes. The inhibitory effect of citalopram in adult rats was unmodified by the two antagonists used, leaving open the possibility that it is mediated by 5-HT3 receptors.
Urbá-Holmgren
R
R
Departamento de Ciencias Fisiologicas, Universidad Autonoma de Puebla, Mexico.
Holmgren
B
B
Leon
B A
BA
Ugarte
A
A
D000375:Aging / Q000523:psychology*; D000818:Animals; D015283:Citalopram / Q000494:pharmacology; D008297:Male; D008719:Methiothepin / Q000494:pharmacology; D010830:Physostigmine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D016713:Ritanserin / Q000494:pharmacology; D012701:Serotonin / Q000502:physiology*; D012702:Serotonin Antagonists / Q000494:pharmacology; D015000:Yawning / Q000502:physiology*
D012702:Serotonin Antagonists; D015283:Citalopram; D016713:Ritanserin; D012701:Serotonin; D008719:Methiothepin; D010830:Physostigmine