Cross references:  GABA   Excitation   Glutamate    Excitation vs. Inhibition       
Sympathetic Nervous System      
Parasympathetic Nervous System       

Searching Google for "nerve inhibition GABA" uncovered 6,660,000 references.     

gamma-Aminobutyric acid - Wikipedia   
    "GABA is the chief inhibitory neurotransmitter in the mammalian central nervous system. Its principal role is reducing neuronal excitability throughout the nervous system."  

Simplified structural formula


    "GABA is synthesized from glutamate via the enzyme glutamate decarboxylase (GAD) with pyridoxal phosphate (the active form of vitamin B6) as a cofactor. This process converts glutamate (the principal excitatory neurotransmitter) into GABA (the principal inhibitory neurotransmitter).[41][42]"  

Searching PubMed for "nerve inhibition GABA" uncovered 2514 references: 


Quick over-views of inhibition pages

        GABA/Glycine Inhibition  

22 references. 
"Glycine and GABA strongly depress the firing of reticulospinal neurons, glycine being more effective than GABA."   
presynaptic GABAB receptor modulation."  

         Tonic Inhibition   
    Searching PubMed for "tonic inhibition" yielded 4981 references:   
     Searching PubMed for "gaba tonic inhibition" yielded 1206 references:  
    Am I really going to review all 1206 references?  GABA tonic inhibition is a very important factor in my hypothetical understanding of behavior, but that's an awful lot of references.   
    Note:  During the course of the review of these references, the number of them rose from 1206 to 1240.  

            Cerebellum Tonic Inhibition       
25 references. 
"... tonic inhibition could be mediated mainly by extrasynaptic alpha6beta2/3delta receptors, whereas phasic inhibition is attributable to the activation of synaptic alpha1beta2/3gamma2, alpha6beta2/3gamma2, and alpha1alpha6beta2/3gamma2 receptors.  
        Amphioxus GABA   
2 references.  "... some sensory cells of the rostral and caudal epidermis, are GABA immunoreactive. "  

        Lamprey Neurotransmitters       

65 references.  
glycine is the natural inhibitory transmitter at these synapses "  
The motor pattern underlying locomotion in the lamprey can be elicited in the spinal cord in vitro by applying excitatory amino acids that activate NMDA receptors."  
     "glycine is the neurotransmitter of these inhibitory reticulospinal neurones." 

        Lamprey GABA 
8 references.  
GABAergic phasic modulation of the membrane potential occurs in spinal interneurons during fictive locomotion in lamprey presumably indicating a presynaptic inhibition."   
3 types of segmental GABA-ir neurons are the main sources of the GABAergic innervation "   
See:   Tonic Inhibition   and   GABA/Glycine Inhibition  .

    Inhibition of Locomotion in Lampreys  
4 references.  
glycine is the neurotransmitter of these inhibitory reticulospinal neurones." 
    "These results suggest that the GABAergic projections to the MLR modulate the activity of MLR neurons, which would be inhibited by GABA at rest." 

        Salamander GABA  
3 references.  
GABAergic central systems, well-developed in the amphibian species"   
immunoreactivity to GABA and glycine"  
"These studies suggest that the steroid recognition sites on GABAA receptors have been highly conserved through vertebrate evolution and thus portend physiologically important functions" 

1972    1168<1180 
Gamma-aminobutyric acid antagonism and presynaptic inhibition in the frog spinal cord.
     The convulsant alkaloid bicuculline blocked presynaptic inhibition, dorsal root potentials, primary afferent depolarization, and depolarizing effects of gamma-aminobutyric acid on dorsal root terminals of the amphibian spinal cord, but did not block effects of other putative amino acid transmitters. These actions of bicuculline suggest that gamma-aminobutyric acid may be the transmitter involved in spinal presynaptic inhibition."  

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