ZFIN ID: ZDB-PUB-070212-36
Early functional development of interneurons in the zebrafish olfactory bulb
Mack-Bucher, J.A., Li, J., and Friedrich, R.W.
Date: 2007
Source: The European journal of neuroscience   25(2): 460-470 (Journal)
Registered Authors: Friedrich, Rainer, Li, Jun
Keywords: none
MeSH Terms:
  • Animals
  • Calcium/metabolism
  • Drug Interactions
  • ELAV Proteins/metabolism
  • ELAV-Like Protein 3
  • GABA Agonists/pharmacology
  • GABA Antagonists/pharmacology
  • Gene Expression Regulation, Developmental/physiology*
  • Green Fluorescent Proteins/metabolism
  • Homeodomain Proteins
  • Imaging, Three-Dimensional/methods
  • Interneurons/drug effects
  • Interneurons/physiology*
  • Muscimol/pharmacology
  • Neural Inhibition/drug effects
  • Odorants*
  • Olfactory Bulb*/cytology
  • Olfactory Bulb*/embryology
  • Olfactory Bulb*/growth & development
  • Pyridazines/pharmacology
  • Zebrafish/physiology*
  • Zebrafish Proteins/metabolism
  • gamma-Aminobutyric Acid/pharmacology
PubMed: 17284187 Full text @ Eur. J. Neurosci.
In the adult olfactory bulb (OB) of vertebrates, local GABAergic interneurons (INs) mediate recurrent and lateral inhibition between the principal neurons of the OB, the mitral cells (MCs), and play pivotal roles in the processing of odor-evoked activity patterns. The properties and functions of INs in the developing OB are, however, not well understood. We studied the functional development of INs in the OB of living zebrafish larvae 3-6 days postfertilization using anatomical techniques and in-vivo two-photon Ca(2+) imaging. We identified MCs and INs by cell-type-specific expression of transgenic fluorescent markers and found that the IN : MC ratio was lower than in the adult fish. Moreover, the fraction of INs responding with Ca(2+) signals to a set of natural odors was substantially lower than in adults. Odors of different chemical classes evoked overlapping patterns of Ca(2+) signals that were concentrated in the center of the IN layer. The GABA(A) receptor agonists GABA and muscimol strongly suppressed odor responses, whereas a GABA(A) receptor antagonist enhanced responses and altered the spatial distribution of odor-evoked activity. These results indicate that IN odor responses at early developmental stages are sparse and exhibit no obvious chemotopic organization. Nevertheless, GABAergic signaling is already inhibitory at early stages of OB development and strongly influences odor-evoked activity patterns. Hence, INs already participate in the processing of odor information at very early stages of OB development even though the majority of INs emerge only at later stages.