Conduction block silences parts of a chemical synapse in the leech central nervous system

E. R. Macagno, Kenneth J Muller, R. M. Pitman

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

1. The pressure (P) sensory neurones innervating the ventral skin of the medicinal leech have receptive fields comprising a central region of skin innervated by two thicker axons and two neighbouring regions innervated by two thinner axons. Impulses originating in the thinner axons may fail to propagate through the central ganglion, apparently blocked at the branch point of large and small axons. 2. The P neurone excites the longitudinal (L) motoneurone, and blocked impulses originating in the anterior fine axon produce e.p.s.p.s that are less than one-half normal amplitude. Blocked impulses in the posterior fine axon are typically ineffective. 3. The branches of P and L neurones, marked with intracellularly injected horseradish peroxidase or with Lucifer Yellow, make synaptic contact at up to sixty-six sites within the neuropile. Of P neurone branches emerging from the two fine axons, those from the posterior axon make fewer contacts, usually one or two at most, while branches from the anterior axon represent no more than half the total contacts. From cell to cell there is some variation in the total number of contacts, the distribution of branches, and the strength of transmission. 4. The locations of contacts measured morphologically correlate well with their distributions as predicted from reductions in e.p.s.p. amplitude during conduction block.

Original languageEnglish
Pages (from-to)649-664
Number of pages16
JournalJournal of Physiology
VolumeVol. 387
StatePublished - Jan 1 1987
Externally publishedYes

Fingerprint

Leeches
Synapses
Axons
Central Nervous System
Neurons
Skin
Neuropil
Motor Neurons
Sensory Receptor Cells
Horseradish Peroxidase
Ganglia
Pressure

ASJC Scopus subject areas

  • Physiology

Cite this

Conduction block silences parts of a chemical synapse in the leech central nervous system. / Macagno, E. R.; Muller, Kenneth J; Pitman, R. M.

In: Journal of Physiology, Vol. Vol. 387, 01.01.1987, p. 649-664.

Research output: Contribution to journalArticle

@article{b282d48a35324489bbe14977386d0a98,
title = "Conduction block silences parts of a chemical synapse in the leech central nervous system",
abstract = "1. The pressure (P) sensory neurones innervating the ventral skin of the medicinal leech have receptive fields comprising a central region of skin innervated by two thicker axons and two neighbouring regions innervated by two thinner axons. Impulses originating in the thinner axons may fail to propagate through the central ganglion, apparently blocked at the branch point of large and small axons. 2. The P neurone excites the longitudinal (L) motoneurone, and blocked impulses originating in the anterior fine axon produce e.p.s.p.s that are less than one-half normal amplitude. Blocked impulses in the posterior fine axon are typically ineffective. 3. The branches of P and L neurones, marked with intracellularly injected horseradish peroxidase or with Lucifer Yellow, make synaptic contact at up to sixty-six sites within the neuropile. Of P neurone branches emerging from the two fine axons, those from the posterior axon make fewer contacts, usually one or two at most, while branches from the anterior axon represent no more than half the total contacts. From cell to cell there is some variation in the total number of contacts, the distribution of branches, and the strength of transmission. 4. The locations of contacts measured morphologically correlate well with their distributions as predicted from reductions in e.p.s.p. amplitude during conduction block.",
author = "Macagno, {E. R.} and Muller, {Kenneth J} and Pitman, {R. M.}",
year = "1987",
month = "1",
day = "1",
language = "English",
volume = "Vol. 387",
pages = "649--664",
journal = "Journal of Physiology",
issn = "0022-3751",
publisher = "Wiley-Blackwell",

}

TY - JOUR

T1 - Conduction block silences parts of a chemical synapse in the leech central nervous system

AU - Macagno, E. R.

AU - Muller, Kenneth J

AU - Pitman, R. M.

PY - 1987/1/1

Y1 - 1987/1/1

N2 - 1. The pressure (P) sensory neurones innervating the ventral skin of the medicinal leech have receptive fields comprising a central region of skin innervated by two thicker axons and two neighbouring regions innervated by two thinner axons. Impulses originating in the thinner axons may fail to propagate through the central ganglion, apparently blocked at the branch point of large and small axons. 2. The P neurone excites the longitudinal (L) motoneurone, and blocked impulses originating in the anterior fine axon produce e.p.s.p.s that are less than one-half normal amplitude. Blocked impulses in the posterior fine axon are typically ineffective. 3. The branches of P and L neurones, marked with intracellularly injected horseradish peroxidase or with Lucifer Yellow, make synaptic contact at up to sixty-six sites within the neuropile. Of P neurone branches emerging from the two fine axons, those from the posterior axon make fewer contacts, usually one or two at most, while branches from the anterior axon represent no more than half the total contacts. From cell to cell there is some variation in the total number of contacts, the distribution of branches, and the strength of transmission. 4. The locations of contacts measured morphologically correlate well with their distributions as predicted from reductions in e.p.s.p. amplitude during conduction block.

AB - 1. The pressure (P) sensory neurones innervating the ventral skin of the medicinal leech have receptive fields comprising a central region of skin innervated by two thicker axons and two neighbouring regions innervated by two thinner axons. Impulses originating in the thinner axons may fail to propagate through the central ganglion, apparently blocked at the branch point of large and small axons. 2. The P neurone excites the longitudinal (L) motoneurone, and blocked impulses originating in the anterior fine axon produce e.p.s.p.s that are less than one-half normal amplitude. Blocked impulses in the posterior fine axon are typically ineffective. 3. The branches of P and L neurones, marked with intracellularly injected horseradish peroxidase or with Lucifer Yellow, make synaptic contact at up to sixty-six sites within the neuropile. Of P neurone branches emerging from the two fine axons, those from the posterior axon make fewer contacts, usually one or two at most, while branches from the anterior axon represent no more than half the total contacts. From cell to cell there is some variation in the total number of contacts, the distribution of branches, and the strength of transmission. 4. The locations of contacts measured morphologically correlate well with their distributions as predicted from reductions in e.p.s.p. amplitude during conduction block.

UR - http://www.scopus.com/inward/record.url?scp=0023162326&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0023162326&partnerID=8YFLogxK

M3 - Article

VL - Vol. 387

SP - 649

EP - 664

JO - Journal of Physiology

JF - Journal of Physiology

SN - 0022-3751

ER -