The involvement of serotonin neurones in the inhibition of renal nerve activity during desynchronized sleep.
Numerous 5-hydroxytryptamine (5-HT)-containing cell bodies were visualized by fluorescence microscopy in the caudal brainstem rostral to the decussation of the pyramids in a region from which a desynchronized sleep-like pattern of sympathetic activity was obtained in a previous study. In unanaesthetized mid-collicular decerebrated cats recordings were made of sympathetic activity in a renal nerve. The inhibition of renal nerve activity occurring during desynchronized sleep-like state induced by physostigmine was attenuated significantly by procedures which interfered with the pathways from the 5-HT-containing neurones. Small cuts in the dorsolateral funiculus of the cervical spinal cord reduced the inhibition from 43 +/- 6% to 14.0 +/- 3%. Microinjection of 5,7-dihydroxytryptamine into cervical spinal cord reduced the serotonin content of the thoracic cord by 22.4% and attenuated the desynchronized sleep-like state inhibition of renal nerve activity by a similar amount. Depletion of serotonin with p-chlorophenylalanine significantly reduced the inhibition of renal nerve activity during the desynchronized sleep-like state, from 42.5 +/- 5% to 10.0 +/- 2.0%. It was suggested that serotonin-containing neurones are likely to be involved in the inhibition of renal nerve activity occurring during desynchronized sleep.
Coote
J H
JH
Futuro Neto
H A
HA
Logan
S D
SD
D015116:5,7-Dihydroxytryptamine / Q000494:pharmacology; D000320:Adrenergic Fibers / Q000502:physiology; D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects; D001933:Brain Stem / Q000166:cytology*; D002415:Cats; D004594:Electrophysiology; D010134:Fenclonine / Q000494:pharmacology; D007668:Kidney / Q000294:innervation*; D009433:Neural Inhibition / Q000187:drug effects; D009434:Neural Pathways / Q000033:anatomy & histology; D012701:Serotonin / Q000378:metabolism*; D012890:Sleep / Q000187:drug effects / Q000502:physiology*; D013116:Spinal Cord / Q000502:physiology
D015116:5,7-Dihydroxytryptamine; D012701:Serotonin; D010134:Fenclonine