Regulatory peptides as modulators of vagal influence on cardiac rhythm
| Autor: | O E Osadchiy, V M Pokrovsky |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
Male
Chronotropic medicine.medical_specialty Physiology Inhibitory postsynaptic potential Tonic (physiology) Electrocardiography Parasympathetic nervous system Delta Sleep-Inducing Peptide Secretin Heart Rate Physiology (medical) Internal medicine Heart rate medicine Animals Neurotensin Pharmacology Chemistry Neuropeptides digestive oral and skin physiology Vagus Nerve General Medicine Enkephalin Leucine-2-Alanine Vagus nerve Autonomic nervous system Endocrinology medicine.anatomical_structure Cats Female Endorphins Electrical conduction system of the heart Somatostatin |
| Zdroj: | Canadian Journal of Physiology and Pharmacology. 73:1235-1245 |
| ISSN: | 1205-7541 0008-4212 |
| DOI: | 10.1139/y95-175 |
| Popis: | When the right vagus nerve of anesthetized cats was stimulated with repetitive bursts of pulses, decelerated heart rate became synchronized to the rhythm of the vagal bursts. Each burst applied to the vagus was followed by a single heart contraction. Within defined limits an increase in the frequency of vagal bursts evoked a proportional acceleration of the heart, whereas a decreased frequency diminished the heart rate. Therefore, over the range of synchronization the heart rate was precisely controlled by changing the vagal stimulation rate. We concluded that the chronotropic effect evoked by vagal bursts was composed of two functionally different types of influence, namely, inhibitory tonic and synchronizing. The vagotropic influence of intravenously injected regulatory peptides was found to be selective for either the tonic or synchronizing component. For instance, dalargin (D-Ala2-Leu5-Arg6-enkephalin) and neokyotorphin selectively diminished the inhibitory tonic vagal influence, whereas delta sleep inducing peptide and neurotensin potentiated it. The magnitude of synchronizing vagal influence was not modified by these peptides. In contrast, secretin selectively inhibited the synchronizing vagal effect, but the tonic one was not affected. Somatostatin potentiated the synchronizing effect but diminished the tonic one. These data support the hypothesis that certain regulatory peptides can modulate the effects of repetitive vagal bursts on pacemaker activity.Key words: vagus nerve, burst stimulation, controlled bradycardia, regulatory peptides. |
| Databáze: | OpenAIRE |
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