Amphioxus Glutamate

Cross references:     Amphioxus Neurotransmitters     Glutamate     
Glutamate Gate       Glutamate Metabotropic Receptor      Subcortical Brain   

Searching for "amphioxus glutamate" yielded:         
        PubMed = 8
        Google = 175,000   

PubMed 1:   
A neurochemical map of the developing amphioxus nervous system    
    See:  Amphioxus Neurotransmitters 

PubMed 3:    
    The amphioxus (Branchiostoma floridae) genome contains a highly diversified set of G protein-coupled receptors.   
    See:  Amphioxus Receptors  .      

PubMed 4:    

N-methyl-D-aspartic acid (NMDA) in the nervous system of the amphioxus Branchiostoma lanceolatum.
    The link leads to an abstract, but the full article comes up when you click on either of two boxes in the upper right corner offering it for free.   
from the Abstract:   
     "NMDA (N-methyl-D-aspartic acid) is a widely known agonist for a class of glutamate receptors, the NMDA type. Synthetic NMDA elicits very strong activity for the induction of hypothalamic factors and hypophyseal hormones in mammals. Moreover, endogenous NMDA has been found in rat, where it has a role in the induction of GnRH (Gonadotropin Releasing Hormone) in the hypothalamus, and of LH (Luteinizing Hormone) and PRL (Prolactin) in the pituitary gland."
     "In this study we show evidence for the occurrence of endogenous NMDA in the amphioxus Branchiostoma lanceolatum."


PubMed 5:
     Free amino acids in the nervous system of the amphioxus Branchiostoma lanceolatum. A comparative study.

    The first page of Google hits, which only numbered 14,100 this time instead of the 175,000 claimed hits last time, provided only one hit not included in the PubMed hits, above, and it wasn't useful.      

    Surprisingly, the second through fourth pages  didn't have anything about glutamate as a neurotransmitter.  Most of the references were about genes and evolution. 

Tuning and playing a motor rhythm: how metabotropic glutamate receptors orchestrate generation of motor patterns in the mammalian central nervous system (Goog) 
Full length HTML available online for free. 
    See also: 
Glutamate Metabotropic Receptor  
from the Abstract:     
    "Repeated motor activities like locomotion, mastication and respiration need rhythmic discharges of functionally connected neurons termed central pattern generators (CPGs) that cyclically activate motoneurons even in the absence of descending commands from higher centres. For motor pattern generation, CPGs require integration of multiple processes including activation of ion channels and transmitter receptors at strategic locations within motor networks. One emerging mechanism is activation of glutamate metabotropic receptors (mGluRs) belonging to group I, while group II and III mGluRs appear to play an inhibitory function on sensory inputs. Group I mGluRs generate neuronal membrane depolarization with input resistance increase and rapid fluctuations in intracellular Ca2+, leading to enhanced excitability and rhythmicity. While synchronicity is probably due to modulation of inhibitory synaptic transmission, these oscillations occurring in coincidence with strong afferent stimuli or application of excitatory agents can trigger locomotor-like patterns. Hence, mGluR-sensitive spinal oscillators play a role in accessory networks for locomotor CPG activation. In brainstem networks supplying tongue muscle motoneurons, group I receptors facilitate excitatory synaptic inputs and evoke synchronous oscillations which stabilize motoneuron firing at regular, low frequency necessary for rhythmic tongue contractions. In this case, synchronicity depends on the strong electrical coupling amongst motoneurons rather than inhibitory transmission, while cyclic activation of KATP conductances sets its periodicity. Activation of mGluRs is therefore a powerful strategy to trigger and recruit patterned discharges of motoneurons. "