5-Hydroxytryptophan (5-HTP) augments spontaneous and evoked phrenic motoneuron discharge in spinalized rats.
Experiments on anesthetized, spinalized rats were conducted to determine the effects of systemic 5-hydroxytryptophan (5-HTP) administration on: (1) spontaneous phrenic nerve activity and (2) evoked phrenic responses to short latency, non-serotonergic synaptic inputs elicited by electrical stimulation of lateral funiculus. 5-HTP augmented spontaneous phrenic activity and allowed expression of a second, longer latency evoked response. Both effects were antagonized by methysergide. Our results suggest that spinal serotonin increases the efficacy of synaptic inputs to phrenic motoneurons.
Mitchell
G S
GS
Department of Comparative Biosciences, University of Wisconsin, Madison 53706.
Sloan
H E
HE
Jiang
C
C
Miletic
V
V
Hayashi
F
F
Lipski
J
J
D006916:5-Hydroxytryptophan / Q000494:pharmacology*; D000818:Animals; D003655:Decerebrate State; D005071:Evoked Potentials / Q000502:physiology; D008784:Methysergide / Q000494:pharmacology; D009046:Motor Neurons / Q000187:drug effects*; D010791:Phrenic Nerve / Q000166:cytology / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains
D006916:5-Hydroxytryptophan; D008784:Methysergide