Muscimol potentiation of acidic amino acid release from cerebellar synaptosomes is chloride dependent
Abstract:
In previous studies we have shown that the depolarization-induced release of preaccumulated acidic amino acids and newly synthesized glutamate from cerebellar synaptosomal preparations is potentiated by gamma-aminobutyric acid (GABA) agonists through a GABAergic presynaptic mechanism. Here we report a systematic analysis of the ionic requirements of the potentiating effect of muscimol on the high K+-evoked release of D-[3H]aspartate. Our studies show that: Ca2+, Na+, and Mg2+ are not required for muscimol to exert its effect; a depolarizing concentration of K+ is a necessary, but not sufficient, condition to observe the presynaptic effect in question; and a minimal Cl- concentration (50-70 mM) is also required. A possible model based on these findings is proposed.
More Related Videos
07:09Subcutaneous Administration of Muscarinic Antagonists and Triple-Immunostaining of the Levator Auris Longus Muscle in Mice
Published on: September 8, 2011
10:45Levator Auris Longus Preparation for Examination of Mammalian Neuromuscular Transmission Under Voltage Clamp Conditions
Published on: May 5, 2018
Related Concept Videos
Chemical Synapses
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
Cholinergic Neurons: Neurotransmission
Cholinergic Receptors: Muscarinic
The subtypes M1, M3, and M5 couple with the Gq subunit and activate the phospholipase C (PLC) activity, mobilizing intracellular Ca2+. Activation...
Direct-Acting Cholinergic Agonists: Chemistry and Structure-Activity Relationship
The direct-acting...
Cholinergic Antagonists: Pharmacological Actions
Gastrointestinal Effects: Antimuscarinics reduce gut contractions, increase gastric emptying, and slow intestinal transit. They partly inhibit gastric acid secretion...
Neuromuscular Junction And Blockade
