Baclofen-induced decrease of excitability of primary afferents and depression of monosynaptic transmission in cat spinal cord

1982 ◽  
Vol 60 (2) ◽  
pp. 160-166 ◽  
Author(s):  
Radan Čapek ◽  
Barbara Esplin
Keyword(s):  
Spinal Cord ◽  
Primary Afferents ◽  
Spinal Reflex ◽  
Primary Afferent Depolarization ◽  
Antagonistic Muscle ◽  
Muscle Nerve ◽  
Relationship Of ◽  
The Relationship ◽  
Excitatory Transmitter ◽  
Terminal Excitability

The relationship of the depressant effect of baclofen on spinal monosynaptic transmission and its effect on the excitability of primary afferents was examined in spinal unanesthetized cats. Baclofen (1.0 mg/kg, i.v.) produced a deep and long-lasting depression of spinal reflex responses with a concomitant decrease of terminal excitability. Primary afferent depolarization, as indicated by an increase of terminal excitability, evoked by conditioning of an antagonistic muscle nerve, was greatly reduced by this drug. Depression of monosynaptic transmission induced by baclofen was temporarily reversed by posttetanic potentiation. However, the same high frequency orthodromic stimulation further reduced excitability of terminals. It is therefore unlikely that block of terminal invasion is responsible for baclofen-induced depression of spinal monosynaptic transmission. These results are compatible with the suggestion that baclofen causes a reduction of transmitter release. In the spinal cord, this action is probably limited to the excitatory transmitter of primary afferents.

Excitability of primary afferents in feline spinal cord: taurine, homotaurine, and γ-aminobutyric acid compared

1982 ◽  
Vol 60 (6) ◽  
pp. 850-855 ◽  
Author(s):  
Radan Čapek ◽  
Barbara Esplin
Keyword(s):  
Primary Afferents ◽  
Aminobutyric Acid ◽  
Primary Afferent Depolarization ◽  
Conditioning Stimulation ◽  
Primary Afferent ◽  
Antagonistic Muscle ◽  
Consistent Change ◽  
Muscle Nerve ◽  
Gaba Synthesis ◽  
Stimulation Of

Effects of taurine and homotaurine (3-aminopropancsuIfonic acid), on excitability of primary afferents were compared with effects of γ-aminobutyric acid (GABA) in spinal unanaesthesized cats. Homotaurine and GABA, administered intravenously or topically, produced a marked increase in afferent excitability. Homotaurine was about 10 times more potent than GABA. Taurine (up to 2 mmol/kg i.v., or 10 mM topically) did not produce a consistent change in afferent excitability. The effect of homotaurine was antagonized by bicuculline or picrotoxin in doses which suppressed the primary afferent depolarization, as indicated by an increase of afferent excitability, evoked by conditioning stimulation of an antagonistic muscle nerve. Semicarbazidc, an inhibitor of GABA synthesis, did not attenuate the homotaurine-induced excitability changes of afferents while suppressing entirely the primary afferent depolarization. These findings suggest that homotaurine exerts a direct GABA-like action on feline primary afferents.

The Relationship of Substance use and the Onset of Spinal Cord Injuries

2019 ◽  
Vol 100 (10) ◽  
pp. e133-e134
Author(s):  
Lori Eldridge ◽  
Jennifer Piatt ◽  
Jon Agley ◽  
Steven Gerke
Keyword(s):  
Spinal Cord ◽  
Substance Use ◽  
Spinal Cord Injuries ◽  
Relationship Of ◽  
The Relationship

scholarly journals Application of multishot diffusion tensor imaging in spinal cord tumors

2019 ◽  
Vol 5 (1) ◽  
pp. 59-64
Author(s):  
Jiefei Li ◽  
Le He ◽  
Yuqi Zhang
Keyword(s):  
Spinal Cord ◽  
Diffusion Tensor Imaging ◽  
Diffusion Tensor ◽  
Preoperative Imaging ◽  
Spinal Cord Tumors ◽  
Intramedullary Tumors ◽  
Routine Magnetic Resonance Imaging ◽  
Relationship Of ◽  
The Relationship ◽  
Diffusion Tensor Imaging Dti

Objective: To explore the usefulness of multishot diffusion tensor imaging (DTI) for evaluating the neurological function of patients with spinal cord tumors Methods: Routine magnetic resonance imaging and multishot DTI were performed in five patients with spinal cord tumors. The values of fractional anisotropy (FA) and radial diffusivity (RD) were analyzed. Results: Multishot DTI of spinal cord tumors allowed for defining the margins of tumors and determining the relationship of tumors with the adjacent white matter structures of the spinal cord. Multishot DTI demonstrated significantly increased RD and decreased FA of spinal cord tumors compared with those of the normal spinal cord. Conclusions: Multishot DTI is a potentially useful modality for differentiating resectable tumors from nonresectable ones based on preoperative imaging alone as well as for differentiating intramedullary tumors from extramedullary ones. Further prospective studies are warranted to confirm these results.

Inhibition of Na+-K+-activated ATPase activity following experimental spinal cord trauma

1978 ◽  
Vol 49 (4) ◽  
pp. 563-568 ◽  
Author(s):  
Nancy R. Clendenon ◽  
Norman Allen ◽  
Wanda A. Gordon ◽  
W. George Bingham
Keyword(s):  
Spinal Cord ◽  
Specific Activity ◽  
Early Time ◽  
Central Core ◽  
Content Type ◽  
Membrane Bound ◽  
And Control ◽  
Relationship Of ◽  
Impact Injury ◽  
The Relationship

✓ The specific activity of the membrane-bound enzyme, Na+-K+-activated adenosine triphosphatase (ATPase), has been shown to be decreased following experimental impact injury (400 gm-cm) to the spinal cord in dogs. The prompt and significant (p < 0.01) fall in activity was evident as early as 5 minutes after injury, and remained at 56% to 67% of control for the 1-hour period studied. This decrease was most prominent in the central core of the traumatized segments of spinal cord. Central core samples, excised immediately adjacent to the trauma site, gave values for the Na+-K+-activated enzyme intermediate to those of the trauma and control sites. For these same samples, the activity of the Mg+2-dependent ATPase did not change appreciably. No alterations were observed in the tissue surrounding the zone of maximum injury at these early time periods. The relationship of membrane-bound enzyme alterations to blood flow, clotting mechanisms, and abnormal free radical reactions are briefly discussed.

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