Electrical activity in myenteric and submucous plexuses of cat intestine

Ohkawa, Hiromichi; Prosser, C. Ladd

doi:10.1152/ajplegacy.1972.222.6.1412

Cited by 45 publications

(16 citation statements)

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“…It would appear that few, if any, of these nerve cells are normally spontaneously active under the conditions of our experiments. This is in contract with the observation of Ohkawa & Prosser (1972a) on the myenteric plexus of the cat. This may be a species difference or may result from the fact that in the experiments on the cat, unlike ours on the guinea-pig, the plexus remained attached to the circular muscle layer and was still in communication with the submucosal plexus.…”

Section: Resultssupporting

confidence: 87%

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Two types of neurones in the myenteric plexus of duodenum in the guinea‐pig

Hirst¹,

Holman²,

Spence³

1974

The Journal of Physiology

438

318

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SUMMARY1. Intracellular recordings have been made from neurones lying in the myenteric plexus of guinea-pig duodenum; some aspects of their membrane properties have been studied by passing current through the intracellular electrode while recording changes in membrane potential.2. The current-voltage relationship was linear for small changes in membrane potential, input resistances ranging from 125 to 250 MQ. Larger hyperpolarizing currents (causing changes of 20-40 mV) caused the input resistance to fall.3. Depolarizing currents of 1 to 10 x 10-10 A initiated action potentials with amplitudes of up to 95 mV. 4. Two types of cell were distinguished when an action potential was initiated. In one group the action potential and undershoot had a form similar to that recorded from other mammalian ganglia. In the second group an action potential was followed by both an undershoot and a prolonged afterhyperpolarization which was associated with a decrease in cell resistance.5. The two groups of cells were further distinguished by their responses to transmural stimulation. Only those cells which did not show an afterhyperpolarization could be shown to receive a synaptic input. 6. The mechanism by which each cell type generates an action potential was different. The action potentials recorded from cells which had a detectable synaptic input were abolished by tetrodotoxin. In contrast, those recorded from the other type of cells persisted in the presence of tetrodotoxin. Preliminary experiments suggest that during an action potential these cells become permeable to both sodium and calcium ions.

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Section: Resultssupporting

confidence: 87%

“…Until recently (Nishi & North, 1973) the only information about the electrical properties of enteric neurones had been obtained from records made with extracellular electrodes (Wood, 1970;Ohkawa & Prosser, 1972a). The latter experiments were done on segments of the small intestine of cats.…”

Section: Introductionmentioning

confidence: 99%

Two types of neurones in the myenteric plexus of duodenum in the guinea‐pig

Hirst¹,

Holman²,

Spence³

1974

The Journal of Physiology

438

318

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“…32 The thiobarbital method was used to determine MDA concentrations, absorbance was measured at 532 nm to determine absorbance and results are expressed as nmol/mg protein. 33 …”

Section: Oxidative Stress Markersmentioning

confidence: 99%

Dose and time effect of CdTe quantum dots on antioxidant capacities of the liver and kidneys in mice

Wang

Sun

Meng

et al. 2017

IJN

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Although quantum dot (QD)-induced toxicity occurs due to free radicals, generation of oxidative stress mediated by reactive oxygen species (ROS) formation is considered an important mechanism. However, free radical mechanisms are essentially difficult to elucidate at the molecular level because most biologically relevant free radicals are highly reactive and short-lived, making them difficult to directly detect, especially in vivo. Antioxidants play an important role in preventing or, in most cases, limiting the damage caused by ROS. Healthy people and animals possess many endogenous antioxidative substances that scavenge free radicals in vivo to maintain the redox balance and genome integrity. The antioxidant capacity of an organism is highly important but seldom studied. In this study, the dose and time effects of CdTe QDs on the antioxidant capacities of the liver and kidneys were investigated in mice using the electron paramagnetic resonance (EPR) spin-trapping technique. We found that the liver and kidneys of healthy mice contain specific antioxidant capacities that scavenge ·OH and ·O 2 − . Furthermore, oxidative stress markers (superoxide dismutase [SOD], catalase [CAT], glutathione peroxidase [GPx], glutathione [GSH] and malondialdehyde [MDA]) were examined. In dose course studies, the free radical scavenging efficiencies of the liver and kidneys were found to gradually decrease with increasing concentration of CdTe QD exposure. The activities and levels of SOD, CAT, GPx and MDA were observed to increase in treated groups, whereas those of GSH were reduced. The time course studies revealed that the QD-induced antioxidant efficiency reduction was time dependent with GSH decrease and could recover after a period of time. These experimental results offer new information on QD toxicity in vivo. Specifically, CdTe QDs can deplete GSH to reduce the elimination ability of the liver and kidneys for ·OH and ·O 2 − , thus inducing oxidative damage to tissues.

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“…One of these behaves like a typical slowly adapting mechanoreceptor, another behaves like a fast-a4apting mechanoreceptor, and the third is activated by mechanical stimulation to discharge prolonged trains of spikes of up to 40 sec duration (35,57). The receptive fi elds of the mechanosensitive neurons are limited to the region of the ganglia and do not extend to the fi ber tracts (43).…”

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confidence: 99%

Intrinsic Neural Control of Intestinal Motility

Wood¹

1981

Annu. Rev. Physiol.

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The structure, synaptic chemistry, and functional properties of the myent eric and submucosal plexuses closely resemble the central nervous system. This consensus emerges from recent reviews of histoanatomical, im munocytochemical, and electrophysiological studies (16,29,62,64). The enteric ganglia are no longer conceived to be simple relay centers that function solely in distribution and divergence of parasympathetic outfl ow to gastrointestinal effector systems. The intrinsic nervous system is now perceived as a "little brain" that communicates with the central nervous system but that also possesses independent integrative circuitry program ming and coordinating activity of the gastrointestinal effector systems. NEUROPHYSIOLOGY OF THE ENTERIC BRAIN Results From Extracellular RecordingSpontaneous and stimulus-evoked patterns of action potential discharge have been recorded extracellularly from neurons within myenteric and submucosal ganglia of intestinal segments from several mammalian species in vitro (14, 43, 49, 57, 60, 64-66, 74, 75) and from rabbits in vivo (42). Three kinds of neuronal units-burst-type units, mechanosensitive units, and single spike units-can be distinguished on the basis of pattern and properties of action potential discharge.BURST-TYPE UNITS Burst-type units discharge periodic bursts of spikes with silent interburst intervals (57,60). The ongoing discharge of the burst type units reflects intrinsic neuronal activity that is not due to electrode induced mechanical irritation as suggested by other authors (38). Evidence for this is: (a) the discharge continues unchanged for many hours;. (b) 33

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Electrical activity in myenteric and submucous plexuses of cat intestine

Cited by 45 publications

References 0 publications

Two types of neurones in the myenteric plexus of duodenum in the guinea‐pig

Two types of neurones in the myenteric plexus of duodenum in the guinea‐pig

Dose and time effect of CdTe quantum dots on antioxidant capacities of the liver and kidneys in mice

Intrinsic Neural Control of Intestinal Motility

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