Pacemaker shift in the gastric antrum of guinea‐pigs produced by excitatory vagal stimulation involves intramuscular interstitial cells
| Autor: | F. R. Edwards, G. D. S. Hirst, Emma J. Dickens |
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| Rok vydání: | 2002 |
| Předmět: |
Boron Compounds
Male medicine.medical_specialty Physiology Guinea Pigs Scopolamine Stimulation Muscarinic Antagonists 4 4'-Diisothiocyanostilbene-2 2'-Disulfonic Acid In Vitro Techniques Biology Inhibitory postsynaptic potential Apamin Nitroarginine Membrane Potentials Pacemaker potential chemistry.chemical_compound Biological Clocks Internal medicine Pyloric Antrum medicine Animals Evoked Potentials Antrum Nerve Endings Stomach Excitatory Postsynaptic Potentials Muscle Smooth Vagus Nerve Original Articles Membrane hyperpolarization Electric Stimulation Endocrinology chemistry Excitatory postsynaptic potential Female Acetylcholine medicine.drug |
| Zdroj: | The Journal of Physiology. 541:917-928 |
| ISSN: | 1469-7793 0022-3751 |
| Popis: | Intracellular recordings were made from isolated bundles of the circular muscle layer of guinea-pig gastric antrum and the responses produced by stimulating intrinsic nerve fibres were examined. After abolishing the effects of stimulating inhibitory nerve terminals with apamin and L-nitroarginine (NOLA), transmural nerve stimulation often evoked a small amplitude excitatory junction potential (EJP) and invariably evoked a regenerative potential. Neurally evoked regenerative potentials had similar properties to those evoked in the same bundle by direct stimulation. EJPs and neurally evoked regenerative potentials were abolished by hyoscine suggesting that both resulted from the release of acetylcholine and activation of muscarinic receptors. Neurally evoked regenerative potentials, but not EJPs, were abolished by membrane hyperpolarization, caffeine and chloride channel blockers. In the intact antrum, excitatory vagal nerve stimulation increased the frequency of slow waves. Simultaneous intracellular recordings of pacemaker potentials from myenteric interstitial cells (ICC(MY)) and slow waves showed that the onset of each pacemaker potential normally preceded the onset of each slow wave but vagal stimulation caused the onset of each slow wave to precede each pacemaker potential. Together the observations suggest that during vagal stimulation there is a change in the origin of pacemaker activity with slow waves being initiated by intramuscular interstitial cells (ICC(IM)) rather than by ICC(MY). |
| Databáze: | OpenAIRE |
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