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G D Fischbach

Publications and source records attributed to G D Fischbach.

97 records · Page 6Linked to original sources
PubMed1970

Synaptic potentials recorded in cell cultures of nerve and muscle.

Initially dissociated spinal cord and muscle cells derived from chick embryos differentiate sufficiently in tissue culture to form functional synaptic contacts. Spontaneous and evoked potentials recorded with intracellular microelectrodes resemble synaptic responses of adult spinal cord and neuromuscular junctions.

Action Potentials↗
PubMed1969

Changes in contractile properties of disused soleus muscles.

1. The hypothesis that the pattern of activity of muscle can determine its contractile properties was tested in the case of the rat soleus subjected to chronic disuse.2. In order to characterize the pattern of motor activity over long periods of time, a method of chronic EMG recording with indwelling electrodes was developed. Some characteristics of the EMG recorded from unrestrained animals are described.3. Immobilization of the knee and ankle joints reduced aggregate EMG activity in the soleus to 5-15% of control and resulted in a shift from tonic to a more phasic pattern of firing.4. After 4 weeks of immobilization, speeding of the soleus mechanical properties was indicated by: shortened contraction time; decreased tetanus/twitch ratio; increased maximum rate of development of tetanic tension; and decreased fusion during a 5/sec tetanus.5. Because the contractile properties of the soleus can be altered by a period of disuse with no change in innervation, neuronal control of the contractile mechanism depends in part on impulse activity.

Animals↗
PubMedDate not supplied

Acetylcholine release from growth cones detected with patches of acetylcholine receptor-rich membranes.

Synaptic potentials can be evoked at nerve-muscle junctions in vitro within minutes after an exploring growth cone contacts a receptive myotube. Functional transmission is also evident in vivo on the time scale of minutes after motor axons enter adjacent myotomes. The ability to release acetylcholine (ACh) may be induced in motor nerve terminals after they contact receptive target cells. Alternately, growth cones may be capable of releasing ACh before contact. To examine the development of ACh release we have used isolated patches of acetylcholine receptor(AChR)-rich membrane as sensitive detectors of ACh. We report here that the growth cones of embryonic chick ciliary ganglion neurones can release ACh, even when the cells are grown in the absence of target myotubes.

Acetylcholine↗