Tonic inhibition is thought to dampen the excitability of principal neurons; however, little is known about the role of tonic GABAergic inhibition in interneurons and the impact on principal neuron excitability. In many brain regions, tonic GABAergic inhibition is mediated by extrasynaptic, δ-subunit-containing GABAA receptors (GABAARs). In the present study we demonstrate the importance of GAB...

In vivo stimulation of a relatively "silent" phasic crayfish motoneuron changes the ultrastructure of its synaptic terminals to a more tonic phenotype. The closer muscle of the crayfish claw is supplied by only 2 excitatory motoneurons, one of which is phasic and the other tonic. The ultrastructures of conditioned phasic, unconditioned phasic, and tonic motor terminals were compared. The termin...

The basis of locomotion is the rhythmic activity of locomotor organs. During walking, rhythmic alternating bursts occur in leg motoneurons which result from the integration of signals from central pattern generators, sense organs and coordinating signals from neighboring segments. The rhythmic bursting pattern is shaped by rhythmic excitatory and inhibitory drive, as well as a long lasting (ton...

Phasic and tonic motor neurons of crustaceans differ strikingly in their junctional synaptic physiology. Tonic neurons generally produce small excitatory postsynaptic potentials (EPSPs) that facilitate strongly as stimulation frequency is increased, and normally show no synaptic depression. In contrast, phasic neurons produce relatively large EPSPs with weak frequency facilitation and pronounce...

Supervising Section Editor: Sean O. Henderson, MD Submission history: Submitted July 5, 2012; Accepted July 30, 2012 Full text available through open access at http://escholarship.org/uc/uciem_westjem DOI: 10.5811/westjem.2012.7.12923 [West J Emerg Med. 2012;13(6):543] Hemal K Kanzaria, MD* Neda Farzan, MD† Zlatan Coralic, PharmD† University of California Los Angeles, Department of Emergency Me...

KEY POINTS Spinal parvalbumin-expressing interneurons have been identified as a critical source of inhibition to regulate sensory thresholds by gating mechanical inputs in the dorsal horn. This study assessed the inhibitory regulation of the parvalbumin-expressing interneurons, showing that synaptic and tonic glycinergic currents dominate, blocking neuronal or glial glycine transporters enhance...

it is well-known that deficiency or over exposure to various elements has noticeable effects on human health. the effect of an element is determined by several characteristics, including absorption, metabolism, and degree of interaction with physiological processes. iron is an essential element for almost all living organisms as it participates in a wide variety of metabolic processes, includin...

Muscular lymphatics use both phasic and tonic contractions to transport lymph for conducting their vital functions. The molecular mechanisms regulating lymphatic muscle contractions are not well understood. Based on the well-established finding that the phosphorylation of myosin light chain 20 (MLC(20)) plays an essential role in blood vessel smooth muscle contraction, we investigated if phosph...

Sudden onset of tonic muscular contraction and loss of consciousness is most often caused by an epileptic seizure. In a seizure, however, the tonic muscular contraction is usually followed by interrupted jerking movements. When the motor pattern remains one of tonic contraction, a different underlying mechanism implying a separate differential diagnosis and therapeutic plan must be considered. ...