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. 1980 Jun;303:423–439. doi: 10.1113/jphysiol.1980.sp013297

The action of serotonin in the rat hippocampal slice preparation.

M Segal
PMCID: PMC1282903  PMID: 6253621

Abstract

1. Intracellular activity was recorded from neurones in the CA1 pyramidal layer of slices of rat hippocampus maintained in vitro. 2. Application of 5-HT in a droplet or via ionophoresis produced a 3-5 mV hyperpolarization associated with a 30% decrease in input resistance. 3. The response to 5-HT was minimal with a drop concentration of 1 microM and maximal with 100 microM. The responses appeared to be blocked by methysergide applied in the superfusion medium. 4. The responses to 5-HT were minimal when the drug was applied in the apical dendritic region and maximal when it was applied near the soma. 5. 5-HT produced no substantial changes in e.p.s.p.s evoked by stimulation of the Schaffer collateral-commissural system or in i.p.s.p.s which were occasionally encountered following stimuli to the stratum radiatum. 6. The responses to 5-HT are true post-synaptic responses and are not indirect effects since they are present in a Ca2+-deficient Mg2+-enriched medium which blocks synaptic transmission. 7. The responses to 5-HT were not dependent on extracellular Cl- concentration. 8. These experiments indicate that 5-HT produces its effects in the rat hippocampus by activating K+ channels.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Andersen P., Bliss T. V., Skrede K. K. Unit analysis of hippocampal polulation spikes. Exp Brain Res. 1971;13(2):208–221. doi: 10.1007/BF00234086. [DOI] [PubMed] [Google Scholar]
  2. Andersen P., Silfvenius H., Sundberg S. H., Sveen O., Wigström H. Functional characteristics of unmyelinated fibres in the hippocampal cortex. Brain Res. 1978 Apr 7;144(1):11–18. doi: 10.1016/0006-8993(78)90431-6. [DOI] [PubMed] [Google Scholar]
  3. Azmitia E. C., Segal M. An autoradiographic analysis of the differential ascending projections of the dorsal and median raphe nuclei in the rat. J Comp Neurol. 1978 Jun 1;179(3):641–667. doi: 10.1002/cne.901790311. [DOI] [PubMed] [Google Scholar]
  4. Barasi S., Roberts M. H. The modification of lumbar motoneurone excitability by stimulation of a putative 5-hydroxytryptamine pathway. Br J Pharmacol. 1974 Nov;52(3):339–348. doi: 10.1111/j.1476-5381.1974.tb08601.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Bennett J. P., Jr, Snyder S. H. Serotonin and lysergic acid diethylamide binding in rat brain membranes: relationship to postsynaptic serotonin receptors. Mol Pharmacol. 1976 May;12(3):373–389. [PubMed] [Google Scholar]
  6. Bloom F. E., Hoffer B. J., Siggins G. R., Barker J. L., Nicoll R. A. Effects of serotonin on central neurons: microiontophoretic administration. Fed Proc. 1972 Jan-Feb;31(1):97–106. [PubMed] [Google Scholar]
  7. Bradley P. B., Briggs I. Further studies on the mode of action of psychotomimetic drugs: antagonism of the excitatory actions of 5-hydroxytryptamine by methylated derivatives of tryptamine. Br J Pharmacol. 1974 Mar;50(3):345–354. doi: 10.1111/j.1476-5381.1974.tb09609.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Conrad L. C., Leonard C. M., Pfaff D. W. Connections of the median and dorsal raphe nuclei in the rat: an autoradiographic and degeneration study. J Comp Neurol. 1974 Jul;156(2):179–205. doi: 10.1002/cne.901560205. [DOI] [PubMed] [Google Scholar]
  9. Cottrell G. A., Macon J. B. Synaptic connexions of two symmetrically placed giant serotonin-containing neurones. J Physiol. 1974 Jan;236(2):435–464. doi: 10.1113/jphysiol.1974.sp010445. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Couch J. R. Further evidence for a possible excitatory serotonergic synapse on raphe neurons of pons and lower midbrain. Life Sci. 1976 Sep 1;19(5):761–767. doi: 10.1016/0024-3205(76)90175-2. [DOI] [PubMed] [Google Scholar]
  11. Gage F. H., Thompson R. G., Valdes J. J. Endogenous norepinephrine and serotonin within the hippocampal formation during the development and recovery from septal hyperreactivity. Pharmacol Biochem Behav. 1978 Sep;9(3):359–367. doi: 10.1016/0091-3057(78)90297-6. [DOI] [PubMed] [Google Scholar]
  12. Gerschenfeld H. M., Paupardin-Tritsch D. Ionic mechanisms and receptor properties underlying the responses of molluscan neurones to 5-hydroxytryptamine. J Physiol. 1974 Dec;243(2):427–456. doi: 10.1113/jphysiol.1974.sp010761. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Kobayashi H., Libet B. Generation of slow postsynaptic potentials without increases in ionic conductance. Proc Natl Acad Sci U S A. 1968 Aug;60(4):1304–1311. doi: 10.1073/pnas.60.4.1304. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Lidov H. G., Molliver M. E., Zecevic N. R. Characterization of the monoaminergic innervation of immature rat neocortex: a histofluorescence analysis. J Comp Neurol. 1978 Oct 1;181(3):663–679. doi: 10.1002/cne.901810311. [DOI] [PubMed] [Google Scholar]
  15. Moore R. Y., Halaris A. E. Hippocampal innervation by serotonin neurons of the midbrain raphe in the rat. J Comp Neurol. 1975 Nov 15;164(2):171–183. doi: 10.1002/cne.901640203. [DOI] [PubMed] [Google Scholar]
  16. Nelson D. L., Herbet A., Bourgoin S., Glowinski J., Hamon M. Characteristics of central 5-HT receptors and their adaptive changes following intracerebral 5,7-dihydroxytryptamine administration in the rat. Mol Pharmacol. 1978 Nov;14(6):983–995. [PubMed] [Google Scholar]
  17. Pellmar T. C., Carpenter D. O. Voltage-dependent calcium current induced by serotonin. Nature. 1979 Feb 8;277(5696):483–484. doi: 10.1038/277483a0. [DOI] [PubMed] [Google Scholar]
  18. Phillis J. W., Tebècis A. K., York D. H. The inhibitory action of monoamines on lateral geniculate neurones. J Physiol. 1967 Jun;190(3):563–581. doi: 10.1113/jphysiol.1967.sp008228. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Roberts M. H., Straughan D. W. Excitation and depression of cortical neurones by 5-hydroxytryptamine. J Physiol. 1967 Nov;193(2):269–294. doi: 10.1113/jphysiol.1967.sp008357. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Sastry B. S., Phillis J. W. Inhibition of cerebral cortical neurones by a 5-hydroxytryptaminergic pathway from median raphé nucleus. Can J Physiol Pharmacol. 1977 Jun;55(3):737–743. doi: 10.1139/y77-099. [DOI] [PubMed] [Google Scholar]
  21. Sawada M., Coggeshall R. E. A central inhibitory action of 5-hydroxytryptamine in the leech. J Neurobiol. 1976 Nov;7(6):477–482. doi: 10.1002/neu.480070602. [DOI] [PubMed] [Google Scholar]
  22. Schwartzkroin P. A. Characteristics of CA1 neurons recorded intracellularly in the hippocampal in vitro slice preparation. Brain Res. 1975 Mar 7;85(3):423–436. doi: 10.1016/0006-8993(75)90817-3. [DOI] [PubMed] [Google Scholar]
  23. Segal M. 5-HT antagonists in rat hippocampus. Brain Res. 1976 Feb 13;103(1):161–166. doi: 10.1016/0006-8993(76)90699-5. [DOI] [PubMed] [Google Scholar]
  24. Segal M., Landis S. Afferents to the hippocampus of the rat studied with the method of retrograde transport of horseradish peroxidase. Brain Res. 1974 Sep 20;78(1):1–15. doi: 10.1016/0006-8993(74)90349-7. [DOI] [PubMed] [Google Scholar]
  25. Segal M. Physiological and pharmacological evidence for a serotonergic projection to the hippocampus. Brain Res. 1975 Aug 22;94(1):115–131. doi: 10.1016/0006-8993(75)90881-1. [DOI] [PubMed] [Google Scholar]
  26. Segal M. The effects of brainstem priming stimulation on interhemispheric hippocampal responses in the awake rat. Exp Brain Res. 1977 Jul 15;28(5):529–541. doi: 10.1007/BF00236475. [DOI] [PubMed] [Google Scholar]
  27. Wang R. Y., Aghajanian G. K. Inhibiton of neurons in the amygdala by dorsal raphe stimulation: mediation through a direct serotonergic pathway. Brain Res. 1977 Jan 14;120(1):85–102. doi: 10.1016/0006-8993(77)90499-1. [DOI] [PubMed] [Google Scholar]
  28. Weight F. F., Salmoiraghi G. C. Serotonin effects on central neurons. Adv Pharmacol. 1968;6(Pt A):395–413. doi: 10.1016/s1054-3589(08)61195-3. [DOI] [PubMed] [Google Scholar]
  29. Yamamoto C. Activation of hippocampal neurons by mossy fiber stimulation in thin brain sections in vitro. Exp Brain Res. 1972;14(4):423–435. doi: 10.1007/BF00235037. [DOI] [PubMed] [Google Scholar]

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