Further studies of the effects of somatostatin and related peptides in area CA1 of rabbit hippocampus

H. E. Scharfman, Philip A Schwartzkroin

Research output: Contribution to journalArticle

23 Scopus citations

Abstract

1. In slice studies of mature and immature CA1 hippocampal pyramidal cells from rabbit, somatostatin 14 (SS14), the related peptide somatostatin 28(1-12) [SS(1-12)], and the synthetic analogue of somatostatin 14, SMS-201995 (SMS), had similar effects. When pressure-ejected onto cell somata, these peptides elicited depolarizations, often accompanied by action potential discharge. When applied to dendrites, the peptides produced depolarizations or hyperpolarizations. 2. When a large amount of one of the three somatostatin-related (SS) peptides was applied to the slice at some distance from the impaled cell, hyperpolarizations were observed that were not always blocked by tetrodotoxin (TTX) or low Ca2+. Since SS peptides were also found to depolarize interneurons in area CA1, it seems likely that the hyperpolarizations that were blocked by TTX or low Ca2+ were mediated via excitation of interneurons that in turn hyperpolarized pyramidal cells. 3. All SS peptides also had long-lasting effects on CA1 pyramidal cells that led to spontaneous firing of action potentials and an increase in the number of action potentials discharged in response to a given depolarizing current pulse; the spontaneous discharge effect was blocked by TTX or low Ca2+ plus Mn2+ and, thus, appeared to have a presynaptic mechanism. However, the increase in discharge in response to a constant depolarizing current pulse was not dependent on intact synaptic transmission and, therefore, was attributable to a direct postsynaptic effect of the SS peptides.

Original languageEnglish (US)
Pages (from-to)411-429
Number of pages19
JournalCellular and Molecular Neurobiology
Volume8
Issue number4
DOIs
StatePublished - Dec 1988
Externally publishedYes

Keywords

  • hippocampal slices
  • interneuron
  • pressure ejection
  • pyramidal cell
  • somatostatin 14
  • somatostatin 28

ASJC Scopus subject areas

  • Neuroscience(all)
  • Genetics
  • Clinical Biochemistry
  • Cell Biology

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