Axonal Localization of an Excitatory Post-Synaptic Potential in a Molluscan Neurone

1970 ◽  
Vol 53 (3) ◽  
pp. 727-737
Author(s):  
A. L. F. GORMAN ◽  
M. MIROLLI
Keyword(s):  
Synaptic Potential ◽  
Lateral Nerve ◽  
Main Trunk ◽  
Synaptic Contacts ◽  
G Cell ◽  
Soma Membrane ◽  
Two Factors ◽  
Input Conductance ◽  
Molluscan Neurone ◽  
Post Synaptic Potential

1. Stimulation of the lateral nerve gives rise to an excitatory post-synaptic potential (EPSP) in the Anisodoris G cell. The amplitude of this EPSP is either unchanged or slightly reduced by moderate hyperpolarization of the soma membrane, whereas stronger hyperpolarization produces an increase. 2. Two factors contribute to this paradoxical behaviour. First, the conductance of the G cell membrane increases when it is hyperpolarized. Second, the apparent changes in cell conductance associated with the EPSP are small relative to the input conductance of the G cell. 3. There are two major regions of the G cell where presumed synaptic contacts can be demonstrated anatomically. The first is on branches of the stem process of the soma in the gastro-oesophageal ganglion neuropile, and the other is on the main trunk of the axon and on axonal branches in the gastro-oesophageal nerve. Presynaptic fibres from the lateral nerve are present in the latter region. No synaptic contacts are found on the soma surface. 4. A comparison of the effects of axonal and somatic polarization on the behaviour of the lateral nerve EPSP indicates that the EPSP occurs on the axon or on axonal branches.

Evidence for a dopamine inhibitory post-synaptic potential in the brain of Helix aspersa

1971 ◽  
Vol 2 (5) ◽  
pp. 15-26 ◽  
Author(s):  
R.J. Walker ◽  
K.L. Ralph ◽  
G.N. Woodruff ◽  
G.A. Kerkut
Keyword(s):  
Helix Aspersa ◽  
Synaptic Potential ◽  
The Brain ◽  
Post Synaptic Potential

Identification of a Prolonged Post-synaptic Potential of Cerebral Cortex.

1959 ◽  
Vol 100 (2) ◽  
pp. 429-431 ◽  
Author(s):  
S. Goldring ◽  
J. L. O'Leary ◽  
D. L. Winter ◽  
A. L. Pearlman
Keyword(s):  
Cerebral Cortex ◽  
Synaptic Potential ◽  
Post Synaptic Potential

The Input-Output Organization Of a Pair of Giant Neurones in the Mollusc, Anisodoris Nobilis (MACFARLAND)

1969 ◽  
Vol 51 (3) ◽  
pp. 615-634
Author(s):  
A. L. F. GORMAN ◽  
M. MIROLLI
Keyword(s):  
Synaptic Contact ◽  
Excitatory Input ◽  
Cell Functions ◽  
G Cells ◽  
G Cell ◽  
Intracellular Stimulation ◽  
Peripheral Cells ◽  
P Cells ◽  
Post Synaptic Potential ◽  
Stimulation Of

1. Each of the two gastro-oesophageal ganglia of the nudibranch mollusc, Anisodoris nobilis, contains one giant neurone (G cell) whose axon is directed toward the oesophagus in the gastro-oesophageal nerve. 2. In the absence of stimulation the G cells are normally silent. However, they receive inhibitory and excitatory synaptic inputs from more central ganglia and a predominantly excitatory input from the periphery. The inputs from the central ganglia are bilaterally distributed to both G cells, whereas the inputs from the periphery are limited to the ipsilateral G cell. 3. Intracellular stimulation shows that there is no interaction between the G cells, nor between the G cell and other cells in the same or contralateral gastro-oesophageal ganglia. 4. The axon of the G cell makes synaptic contact with a series of peripheral cells (P cells). In most P cells the post-synaptic potential elicited by intracellular stimulation of the G cell is constant in amplitude and latency and probably results from a unitary monosynaptic contact. Intracellular stimulation shows that the P cells are not connected to the G cell. 5. The P cells are inter-connected by low-resistance electrotonic junctions which allow slow potentials of either polarity to spread between cells. These junctions exist between distant as well as adjacent peripheral neurones. 6. Our results show that the G cell functions as a command interneurone for an aggregate of electrically interconnected peripheral neurones.

Synapses upon motoneurons of locusts during retrograde degeneration

1974 ◽  
Vol 269 (896) ◽  
pp. 95-108 ◽  
Keyword(s):  
Time Constant ◽  
Synaptic Potential ◽  
Progressive Reduction ◽  
Retrograde Degeneration ◽  
Synaptic Inputs ◽  
Progressive Loss ◽  
Peripheral Section ◽  
Metathoracic Ganglion ◽  
Movement Detectors ◽  
Post Synaptic Potential

Four interneurons of the ventral cord, the descending movement detectors (DMD) have symmetrical synapses upon the fast extensor tibiae (FETi) motoneurons on each side of the metathoracic ganglion. Each impulse in a DMD interneuron generates an excitatory post-synaptic potential (e.p.s.p.) of constant and similar amplitude in both FETi motoneurons of a normal locust. The symmetry provides inherent controls which makes this a convenient system to study the effect on inputs to a motoneuron caused by peripheral section of its axon. On the operated side the retrograde changes in the FETi motoneuron include, first an increased amplitude of the e.p.s.ps, then a brief period when they are variable, followed by a progressive reduction over a period of days. Other inputs to the FETi motoneurons from head, abdomen and tympanum also decline, but not at equal rates. Changes in e.p.s.p. amplitude are the opposite to those expected from simultaneous changes in the time constant. The observed changes in the e.p.s.ps are attributed to instability and then progressive loss of synapses upon the FETi motoneuron. The results show that the integrity of the motoneuron is essential for maintenance of its synaptic inputs.

Inhibitory Post-Synaptic Potential (IPSP)

2016 ◽  
Author(s):  
Douglas M. Templeton ◽  
Michael Schwenk ◽  
John H. Duffus
Keyword(s):  
Synaptic Potential ◽  
Post Synaptic Potential
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