Serotonin excites arcuate neurons directly but inhibits them through intercalate d GABAergic neurons

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Journal Title:
Volume 54, Issue 03, 2002
Key Word:
arcuate nucleus;neurons;serotonin;cyproheptadine;bicuculline;brain slice

Abstract: Effects of serotonin (5-HT) on spontaneous discharges of single hypothalam ic arcuate neurons were observed in rat brain slices by extracellular recordin gs. The results showed that (1) of 149 neurons selected randomly and tested for 5-HT application, 33 (22.2%) were excited, 82 ( 55.0%) were inhibited, and 34 (22.8%) showed biphasic responses or failed to respond; (2) substitution of low Ca2+-high Mg2+ artificial cerebrospinal fluid (aCSF) for normal aCS F abolished the 5-HT-induced inhibitory effect but failed to affect the 5-HT-induced excitatory effect; (3) cyproheptadine, a non-selective 5-HT receptor antagonist, could block either the 5-HT-induced excitatory or inhibitory effects in all neurons tested; and (4) bicuculline, a GABAA -rece ptor antagonist, blocked the 5-HT-induced inhibitory effect. These result s imply (1) 5-HT excites arcuate neurons through a mechanism that is insen sitive to the decreased extracellular Ca2+, suggesting a direct postsynapt ic action of 5-HT on the 5-HT-receptors located in the membrane of th e neurons recorded; and (2) 5-HT might elicit the inhibitory effect through a Ca2+-sensitive release of GABA from intercalated GABAergic local neuro ns that are excited first by 5-HT.

  • [1]Alreja M.Excitatory actions of serotonin on GABAergic neurons of the medial sep tum and diagonal band of Broca.Synapse,1996,22(1):15~27.
  • [2]Baker RA,Herkenham M.Arcuate nucleus neurons that project to the hypothalamic paraventricular nucleus: neuropeptidergic identity and consequences of adrenale ctomy on mRNA levels in the rat.J Comp Neurol,1995,358:518~530.
  • [3]Bloom FE,Battenberg E,Rossier J,Ling N,Guillemin R.Neurons containing β- endorphin in rat brain exist separately from those containing enkephalin: immuno cytochemical studies.Proc Natl Acad Sci USA,1978,75:1591~1595.
  • [4]Barnes NM,Sharp T.A review of central 5-HT receptors and their function.Neuropharmacology,1999,38:1083~1152.
  • [5]Chen QL (陈起亮),Li JH(李金华),Zhou ZJ(周志菁),Yin QZ (印其章).Effects of lesion or stimulation of pituitary gland and hypotha lamic arcuate nucleus on pain modulation in rats.Acta Physiol Sin (生理学报) ,1995,47(5):505~509 (Chinese,English abstract).
  • [6]Dahlstrm A,Fuxe K.Evidence for the existence of monoamine containing neurons in the central nervous system.I.Demonstration of monoamines in the cell bodie s of brainstem neurons.Acta Physiol Scand,1964,Suppl 232: 1~55.
  • [7]Dorsa DM,Majumdar LA.Localization and identification of β-endorphin and β -endorphin-like peptides in the rat.Life Sci,1983,33:337~345.
  • [8]Duanmu ZX(端木肇夏),Zhang YJ(张跃进),Zhang HQ(张惠琴),Yin QZ (印其章).Effect of raphe dorsalis and locus coeruleus stimulation on ev oked potential in hypothalamic arcuate nucleus area.Acta Physiol Sin(生理学报) ,1985,37(6):517~524 (Chinese,English abstract).
  • [9]Garcia YE,Pelletier G.Negatively regulation of proopiomelanocortin gene expre ssion by GABAA receptor activation in the rat arcuate nucleus.Peptides,1994,15 :615~618.
  • [10]Grzanna R,Molliver ME.The locus coeruleus in the rat: an immunohistochemical d elineation.Neuroscience,1980,5:21~40.
  • [11]Horvath TL,Bechmann I,Naftolin F,Kalra SP,Laranth C.Heterogeneity in the n europeptide Y-containing neurons of the rat arcuate nucleus: GABAergic and non -GABAergic subpopulations.Brain Res Bull,1997,756:283~286.
  • [12]Hoyer D,Clarke DE,Fozard JR,Hartig PR,Martin GR,Mylecharane EJ,Saxena PR.International union of pharmacology classification of receptors for 5-hydroxytr yptamine (serotonin).Pharmacol Rev,1994,46:157~203.
  • [13]James CW,Finley P,Peter P.Immunocytochemical localization of β-endorphin-c ontaining neurons in the rat brain.Neuroendocrinology,1981,33:28~42.
  • [14]Jiao YY(矫勇益),Duanmu ZX(端木肇夏),Yu GD(俞光第),Yin QZ (印其章).Inhibitory effects of hypothalamic arcuate nucleus or anter ior pituitary stimulation on the nociceptive responses of thalamic parafascicula r neurons.Acta Physiol Sin (生理学报),1995,47(5):423~428 (Chinese,English abstract).
  • [15]Kang YM,Ouyang W,Chen JY,Qiao JT,Dafny H.Norepinephrine modulates single hy pothalamic arcuate neurons via α- and β-adrenergic receptors.Brain Res,20 01,869:146~157.
  • [16]Kitzman P,Bishop G.The physiological effects of serotonin on spontaneous and a mino acid-induced activation of cerebellar nuclear cells : an in vivo study in the rat.Prog Brain Res,1997,114:209~223.
  • [17]Loose MD,Kelly MJ.Opioid inhibition of spontaneously active neurons of the rat arcuate nucleus in vitro.Brain Res Bull,1989,22:819~823.
  • [18]Loose MD,Ronnekle OK,Kelly MJ.Neurons in the rat arcuate nucleus are hype rpolarized by GABA and mu-opioid receptor agonists: evidence for convergence a t a ligand-gated potassium conductance.Neuroendocrinology,1991,54:537~544.
  • [19]MacMillan SJ.Discharge characteristics and distribution of arcuate neurons fr om rat hypothalamic record in vitro.J Physiol (Lond),1983,338:44~52.
  • [20]Millan MJ,Gramsch C,Przewtocki R,Hllt V,Herz A.Lesions of the hypothal amic arcuate nucleus produce a temporary hyperalgesia and attenuate stress-evo ked analgesia.Life Sci,1980,27:1513~1523.
  • [21]Okuya S,Yamamoto H.Effects of atrial natriuretic polypeptide on rat hyp othalamic neurons in vitro.J Physiol (Lond),1987,389:717~729.
  • [22]Peroutka SJ.5-Hydroxytryptamine receptor subtypes.An nu Rev Neurosci,1988,11:45~60.
  • [23]Rainnie DG.Serotonergic modulation of neurotransmission in the basolateral amy gdala.J Neurophysiol,1999,82:69~85.
  • [24]Sim LJ,Joseph SA.Arcuate nucleus projections to brainstem regions which modul ate nociception.J Chem Neuroanat,1991,4:97~109.
  • [25]Stutzmann GE,Ledoux JE.GABAergic antagonists block the inhibitory effects of s erotonin in the lateral amygdala: A mechanism for modulation of sensory inputs r elated to fear conditioning.J Neurosci,1999,19(23):RC8:1~4.
  • [26]Tao P (陶萍),Mei J (梅俊).Effects of 5-HT on activity of arcuate neuro n of rat hypothalamic slices.Acta Physiol Sin (生理学报),1996,48(2):157~164 (Chinese,English abstract).
  • [27]Wang Q,Mao LM,Han JS.Characterization of inhibition of spinal nociceptive re flex by stimulation of the arcuate nucleus of the hypothalamus in the pentobarbi tal-anesthetized rat.Pain,1990,41:101~108.
  • [28]Willough JO,Blessing W.Origin of serotonin innervation of the arcuate and ven tromedial hypothalamic region.Brain Res,1978,418:170~173.
  • [29]Wilson JA,Lau YS,Gleeson JG,Wilson JS.The action of MPTP on synaptic trans mission is affected by changes in Ca2+ concentrations.Brain Res,1991,541:342~346.
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