5-HT and 5-HT-SO4, but not tryptophan or 5-HIAA levels in single feeding neurons track animal hunger state.
Serotonin (5-HT) is an intrinsic modulator of neural network excitation states in gastropod molluscs. 5-HT and related indole metabolites were measured in single, well-characterized serotonergic neurons of the feeding motor network of the predatory sea-slug Pleurobranchaea californica. Indole amounts were compared between paired hungry and satiated animals. Levels of 5-HT and its metabolite 5-HT-SO4 in the metacerebral giant neurons were observed in amounts approximately four-fold and two-fold, respectively, below unfed partners 24 h after a satiating meal. Intracellular levels of 5-hydroxyindole acetic acid and of free tryptophan did not differ significantly with hunger state. These data demonstrate that neurotransmitter levels and their metabolites can vary in goal-directed neural networks in a manner that follows internal state.
Department of Molecular & Integrative Physiology, Department of Chemistry and Beckman Institute, University of Illinois, Urbana, Illinois, USA.
N G
NG
Hatcher
X
X
Zhang
J N
JN
Stuart
L L
LL
Moroz
J V
JV
Sweedler
R
R
Gillette
D000818:Animals; D005247:Feeding Behavior / Q000502:physiology*; D017952:Ganglia, Invertebrate / Q000737:chemistry / Q000378:metabolism; D006815:Hunger / Q000502:physiology*; D006897:Hydroxyindoleacetic Acid / Q000032:analysis / Q000378:metabolism*; D009415:Nerve Net / Q000737:chemistry / Q000378:metabolism; D009474:Neurons / Q000737:chemistry / Q000378:metabolism*; D049853:Pleurobranchaea; D012527:Satiation / Q000502:physiology; D012701:Serotonin / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism*; D014364:Tryptophan / Q000032:analysis / Q000378:metabolism*
C033396:5-hydroxytryptamine O-sulfate; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D014364:Tryptophan