PMID- 6747859
OWN - NLM
STAT- MEDLINE
DCOM- 19840824
LR  - 20190511
IS  - 0022-3751 (Print)
IS  - 1469-7793 (Electronic)
IS  - 0022-3751 (Linking)
VI  - 350
DP  - 1984 May
TI  - Synaptic input from identified muscle afferents to neurones of the dorsal 
      spinocerebellar tract in the cat.
PG  - 599-614
AB  - Single identified group I a and I b muscle afferent fibres were injected with 
      horseradish peroxidase in the lumbar dorsal columns of anaesthetized cats. The 
      morphological details of the axon collaterals and terminal boutons of these 
      muscle afferents within Clarke's column were subsequently reconstructed. The 
      rostro-caudal extent of synaptic terminals from a single afferent fibre within 
      Clarke's column was found to be restricted to less than 1 mm. In the same 
      experiments, dorsal spinocerebellar tract (d.s.c.t.) neurones were retrogradely 
      labelled by injection of horseradish peroxidase into the cerebellum. Synaptic 
      contacts between labelled group Ia and Ib afferent fibres and the soma and 
      proximal dendrites of d.s.c.t. neurones were found. The synaptic contacts from 
      both Ia and Ib fibres varied greatly in size, from 1 X 1 micron up to 'giant' 
      synapses of 20 X 3 micron. Excitatory post-synaptic potentials (e.p.s.p.s) were 
      evoked in d.s.c.t. neurones by impulses in single group I muscle afferent fibres. 
      The fluctuations in peak amplitude of each e.p.s.p. were determined from e.p.s.p. 
      and noise recordings, using a numerical deconvolution procedure. In general, 
      these single-fibre e.p.s.p.s fluctuated between discrete amplitudes separated by 
      an incremental amplitude which was approximately constant. This incremental 
      amplitude did not depend on the average peak amplitude of the particular e.p.s.p. 
      examined. Our anatomical observations of 'giant' boutons arising from Ia and Ib 
      afferent fibres contacting d.s.c.t. neurones raises the possibility of multiple 
      transmitter release sites within an individual synaptic bouton. It is proposed 
      that synaptic transmission between group I muscle afferents and d.s.c.t. neurones 
      occurs with discrete all-or-nothing e.p.s.p.s associated with transmitter release 
      sites.
FAU - Tracey, D J
AU  - Tracey DJ
FAU - Walmsley, B
AU  - Walmsley B
LA  - eng
PT  - Journal Article
PL  - England
TA  - J Physiol
JT  - The Journal of physiology
JID - 0266262
SB  - IM
MH  - Action Potentials
MH  - Animals
MH  - Cats
MH  - Dendrites/ultrastructure
MH  - Hindlimb
MH  - Muscles/*innervation
MH  - Neurons/*physiology
MH  - Neurons, Afferent/*physiology/ultrastructure
MH  - Spinal Cord/*cytology
MH  - Synapses/*physiology/ultrastructure
MH  - Time Factors
PMC - PMC1199288
EDAT- 1984/05/01 00:00
MHDA- 1984/05/01 00:01
PMCR- 1984/05/01
CRDT- 1984/05/01 00:00
PHST- 1984/05/01 00:00 [pubmed]
PHST- 1984/05/01 00:01 [medline]
PHST- 1984/05/01 00:00 [entrez]
PHST- 1984/05/01 00:00 [pmc-release]
AID - 10.1113/jphysiol.1984.sp015220 [doi]
PST - ppublish
SO  - J Physiol. 1984 May;350:599-614. doi: 10.1113/jphysiol.1984.sp015220.