AIM To study the effects of ciliary neurotrophic factor (CNTF) on the expressions of gentamicin ototoxicity in guinea pigs. METHODS The auditory function of pigmented guinea pigs was examined using auditory brainstem response (ABR), cochlea microphonic potential (CM), and action potential of auditory nerve (AP). RESULTS In animals injected gentamicin (80 mg.kg-1.d-1, i.m.), ABR threshold be...

Transtympanic electrocochleography using rarefaction and condensation clicks was performed on 122 ears of 112 patients, including 98 ears of 89 patients with Menière's disease (MD) and 24 ears of 23 patients without Menière's disease (NMD). The mean action potential (AP) latency difference between rarefaction and condensation clicks was 0.40 +/- 0.37 msec in the MD group and 0.06 +/- 0.07 msec ...

Electrocochleography (ECochG) has evolved as an important tool in the diagnosis/assessment/monitoring of Ménière's disease/endolymphatic hydrops (MD/ELH). This manuscript provides an update on the use of ECochG for these purposes. The material presented includes descriptions of the components of the electrocochleogram; ECochG recording approaches and parameters; how to prepare for an exam, incl...

Lysophosphogiycerides and long-chain acyl carnitines accumulate in igchemic myocardium soon after coronary occlusion. Since both are amphiphi.cs and have some structural similarities, we studied their clectrophysiological effects on transmembrane action potentials (AP) of isolated canine Purkinje fibers. Lysophosphatidyl choline (LPC) in the absence of albumin induced concentration-dependent (7...

Spatial dispersion of repolarization is known to play an important role in arrhythmogenesis. Electrotonic modulation of repolarization by the activation sequence has been observed in some species and tissue preparations, but to varying extents. Our study sought to determine the mechanisms underlying species- and tissue-dependent electrotonic modulation of repolarization in ventricles. Epi-fluor...

The effects of some cholinergic agents and 4-aminopyridine (4-AP) on neurally mediated contractions of in vitro cat ciliary muscle preparations were studied. The contractile response to trains of stimuli was enhanced by eserine and completely blocked by tetrodotoxin or atropine. Low concentrations of carbachol did not modify muscle resting tension but clearly attenuated contractile response to ...

Although several transducer molecules for noxious stimuli have been identified, little is known about the transformation of the resulting generator currents into action potentials (APs). Therefore we investigated the transformation process for stepped noxious heat stimuli (42-47 degrees C, 3-s duration) into membrane potential changes and subsequent AP discharges using the somata of acutely dis...

AIM To investigate the effects of artemisinin (Art) on the action potentials (AP) recorded from identified C-type nodose neurons and study its anti-arrhythmic and anesthetic mechanisms. METHODS Neonatal and adult rats were selected for the preparation of isolated nodose ganglia neurons (NGN) and nodose ganglion-vagus slice preparation. Somatic AP were recorded from both isolated and slice NGN...

This paper investigates the impact of increased salinity on touch-induced receptor and action potentials of Chara internodal cells. We resolved underlying changes in ion transport by current/voltage analysis. In a saline medium with a low Ca(2+) ion concentration [(Ca(2+))(ext)], the cell background conductance significantly increased and proton pump currents declined to negligible levels, depo...

The double sucrose-gap method was applied to single muscle fibers of Xenopus. From the "artificial node" of the fiber, action potentials were recorded under current-clamping condition together with twitches of the node. The action potentials were stored on magnetic tape. The node was then made inexcitable by tetrodotoxin or by a sodium-free solution, and the wave form of the action potential st...