Presynaptic modulation of ganglionic ACh release by muscarinic and nicotinic receptors

1990 ◽  
Vol 259 (2) ◽  
pp. R288-R293
Author(s):  
Z. Dujic ◽  
D. L. Roerig ◽  
H. K. Schedewie ◽  
J. P. Kampine ◽  
Z. J. Bosnjak
Keyword(s):  
Synaptic Transmission ◽  
Nicotinic Receptors ◽  
Stellate Ganglion ◽  
Feedback Regulation ◽  
Compound Action Potential ◽  
Presynaptic Receptors ◽  
Ach Release ◽  
Ganglionic Transmission ◽  
Muscarinic And Nicotinic Receptors ◽  
Compound Action

The present experiments were undertaken to investigate the effects of atropine and d-tubocurarine on acetylcholine (ACh) release and ganglionic synaptic transmission in the isolated cat stellate ganglion. Ganglionic release of picomole amounts of ACh was measured by radioenzymatic assay, and ganglionic transmission was estimated on the basis of the compound action potential recorded from the postganglionic stellate cardiac nerve. Atropine (5 microM) produced a significant increase in both spontaneous and evoked ACh release from the ganglion while depressing synaptic transmission. d-Tubocurarine (20 microM) also caused a significant, though smaller, increase in spontaneous release of ACh but had little effect on evoked release of ACh. These results suggest that ACh release and synaptic transmission in the cat stellate ganglion are subject to cholinergic feedback regulation, which appears to be mediated predominantly via muscarinic presynaptic receptors.

scholarly journals Effect of Chronological Age on Pulse Rate Discrimination in Adult Cochlear-Implant Users

2021 ◽  
Vol 25 ◽  
pp. 233121652110073
Author(s):  
Kelly C. Johnson ◽  
Zilong Xie ◽  
Maureen J. Shader ◽  
Paul G. Mayo ◽  
Matthew J. Goupell
Keyword(s):  
Pulse Rate ◽  
Compound Action Potential ◽  
Action Potential Amplitude ◽  
Growth Functions ◽  
Evoked Compound Action Potential ◽  
Rate Discrimination ◽  
Amplitude Growth ◽  
Temporal Pulse ◽  
Compound Action Potential Amplitude ◽  
Compound Action

Cochlear-implant (CI) users rely heavily on temporal envelope cues to understand speech. Temporal processing abilities may decline with advancing age in adult CI users. This study investigated the effect of age on the ability to discriminate changes in pulse rate. Twenty CI users aged 23 to 80 years participated in a rate discrimination task. They attempted to discriminate a 35% rate increase from baseline rates of 100, 200, 300, 400, or 500 pulses per second. The stimuli were electrical pulse trains delivered to a single electrode via direct stimulation to an apical (Electrode 20), a middle (Electrode 12), or a basal location (Electrode 4). Electrically evoked compound action potential amplitude growth functions were recorded at each of those electrodes as an estimate of peripheral neural survival. Results showed that temporal pulse rate discrimination performance declined with advancing age at higher stimulation rates (e.g., 500 pulses per second) when compared with lower rates. The age-related changes in temporal pulse rate discrimination at higher stimulation rates persisted after statistical analysis to account for the estimated peripheral contributions from electrically evoked compound action potential amplitude growth functions. These results indicate the potential contributions of central factors to the limitations in temporal pulse rate discrimination ability associated with aging in CI users.

scholarly journals Can auditory brain stem response accurately reflect the cochlear function?

2020 ◽  
Vol 124 (6) ◽  
pp. 1667-1675
Author(s):  
Dalian Ding ◽  
Jianhui Zhang ◽  
Wenjuan Li ◽  
Dong Li ◽  
Jintao Yu ◽  
...  
Keyword(s):  
Brain Stem ◽  
Damage Model ◽  
Compound Action Potential ◽  
Cochlear Function ◽  
Auditory Brain Stem Response ◽  
Threshold Difference ◽  
Auditory Brain Stem ◽  
Cochlear Damage ◽  
Brain Stem Response ◽  
Compound Action

Auditory brain stem response (ABR) is more commonly used to evaluate cochlear lesions than cochlear compound action potential (CAP). In a noise-induced cochlear damage model, we found that the reduced CAP and enhanced ABR caused the threshold difference. In a unilateral cochlear destruction model, a shadow curve of the ABR from the contralateral healthy ear masked the hearing loss in the destroyed ear.

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