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Neurons
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
Plateau potentials have been observed in neurons other than motoneurons, such as cerebellar Purkinje cells, neocortical pyramidal neurons, and striatal neurons. But not all plateau potentials are due to dendritic instability, as, for example, the plateau potential in Figure 7.8.
The Neurobiology of Central Sensitization
Published in Robert M. Bennett, The Clinical Neurobiology of Fibromyalgia and Myofascial Pain, 2020
Discharge of primary afferent nociceptors at high frequencies, produced by more intense or sustained noxious stimuli, results in corelease of peptide neuromodulators such as substance P and calcitonin gene-related peptide from nociceptor central terminals which leads to slow synaptic potentials lasting tens of seconds (2) as illustrated in Figure 2. These slow EPSPs provide substantial opportunities for temporal summation of fast EPSPs (3) and the cumulative depolarization is boosted by the recruitment of NMDA receptor current upon removal of the Mg2+ blockade of the channels. The sustained depolarization also recruits voltage-gated calcium [Ca2+] currents, triggering plateau potentials mediated by calcium-activated nonselective cation channels. The net effect of these multiple processes in dorsal horn pain transmission neurons is a progressive increase in the action potential discharge elicited by each stimulus, a phenomenon known as “windup” (4).
What is Spasticity?
Published in Valerie L. Stevenson, Louise Jarrett, Spasticity Management, 2016
Spasms may be predominantly flexor, extensor or a combination of both (with or without adduction). Flexor spasms (sudden ankle dorsiflexion or knee and hip flexion) may be caused by disinhibited polysynaptic reflexes such as the flexor withdrawal reflex (a normal response in humans that is triggered by a noxious stimulus to the foot, such as standing on a nail). Spasms may also reflect activity in disinhibited pathways involved in the coordination of leg movements while walking,119–121 or may reflect abnormal activity within spinal cord circuits that have the effect of synchronising the discharge of the motor neurons supplying multiple muscles.122,123 The development of abnormal plateau potentials in motorneurons (see above) is also felt to contribute to the long-lasting flexor or extensor responses and ‘wind up’ – the increase in motor response with repeated activation.124,125
Pinocembrin ameliorates arrhythmias in rats with chronic ischaemic heart failure
Published in Annals of Medicine, 2021
Yan Guo, Cui Zhang, Tianxin Ye, Xiuhuan Chen, Xin Liu, Xiaoli Chen, Yazhou Sun, Chuan Qu, Jinjun Liang, Shaobo Shi, Bo Yang
Moreover, plateau potentials were decreased in the CIHF-PZ (2.81 ± 0.35 mV) and showed a tendency of prolongation in the CIHF-RZ (8.59 ± 0.43 mV). Meanwhile, pinocembrin exhibited positive effects on CIHP-PZ (6.39 ± 0.80 mV) and CIHP-RZ (6.17 ± 0.56 mV). However, there was no change in APA and the maximal upstroke velocity (dV/dt) among the zones of the SHAM, CIHF, and CIHP groups, respectively (Figure 2(E–G)).