Quantitative analysis and postsynaptic targets of GABA-immunoreactive boutons within the rat trigeminal motor nucleus

Sikha Saha, Kwabena Appenteng, Trevor F C Batten

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)

Abstract

We have used the post-embedding immunogold labelling method using antibodies to γ-aminobutyric acid (GABA) to obtain quantitative data on the distribution, frequency, postsynaptic targets and ultrastructural characteristics of GABA-immunoreactive (GABA-IR) boutons in the trigeminal motor nucleus of rats. We have also combined this method with horseradish peroxidase tracing to obtain specific evidence for termination of some GABA-IR boutons onto identified jaw-elevator motoneurones. Twenty-eight percent of all synapses in the motor nucleus involved GABA-IR boutons. Seventy-three percent of the GABA-IR boutons formed axo-dendritic synapses, 13% axo-somatic synapses and 14% axo-axonic synapses. Ninety-three percent of GABA-IR boutons formed symmetrical synapses. Overall, 58% of all boutons contained only flattened vesicles, while 26% contained round vesicles and 16% a mixture of vesicle types. Measurements of bouton crops sectional area, apposition length, and active zone length were obtained from serial reconstructions of 15 GABA-IR boutons and 30 unlabelled boutons. In each case mean values for GABA-IR boutons were significantly smaller than those for nonlabelled boutons.
Original languageEnglish
Pages (from-to)128-138
Number of pages11
JournalBrain Research
Volume561
Issue number1
DOIs
Publication statusPublished - 4 Oct 1991
Externally publishedYes

Keywords

  • Electron microscopy
  • Motoneuron
  • Synapse
  • Trigeminal
  • γ-Aminobutyric acid

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