Activation of sympathetic nerves exerts an inhibitory influence on afferent nerve-induced vasodilation unrelated to vasoconstriction in rat dental pulp
| Autor: | Leif Olgart, A. Funato, Lennart Edwall, N. P. Kerezoudis |
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| Rok vydání: | 1993 |
| Předmět: |
Male
medicine.medical_specialty Sympathetic nervous system Sympathetic Nervous System Physiology Phenoxybenzamine Vasodilation Rats Sprague-Dawley Phentolamine Internal medicine medicine Prazosin Animals Neurons Afferent Infusions Intravenous Adrenergic alpha-Antagonists Dental Pulp Ganglia Sympathetic business.industry Electric Stimulation Ganglionectomy Rats Incisor Atropine medicine.anatomical_structure Endocrinology Regional Blood Flow Vasoconstriction medicine.symptom Capsaicin business Idazoxan medicine.drug |
| Zdroj: | Acta physiologica Scandinavica. 147(1) |
| ISSN: | 0001-6772 |
| Popis: | In order to elucidate a possible influence of the sympathetic nervous system on afferent nerve function, rat mandibular incisors were electrically stimulated and blood flow changes monitored in the incisor pulp of untreated and sympathectomized animals by a laser Doppler flowmeter. Monopolar electrical stimulation of the tooth (200 microA, 5 ms, 40 Hz, 1 s) in normal animals resulted in a transient reduction in pulpal blood flow (PBF) (16% reduction, n = 10) followed by a small but long-lasting increase (11% increase). After administration of phenoxybenzamine or phentolamine (3 mg kg-1, i.v.) the initial dip in PBF was reduced by 59% (P < 0.001) while the subsequent increase was enhanced by 185% (P < 0.001). Similarly, infusion of prazosin (50 micrograms kg-1, i.v.) and idazoxan (0.5 mg kg-1, i.v.) significantly enhanced the increase in PBF by 118 and by 79%, respectively. In chronically sympathectomized animals the increase in PBF was 250% larger than that seen in untreated animals (P < 0.001). This increase in PBF was not further enhanced after alpha-adrenergic blockade. Acute resection of the superior cervical sympathetic ganglion, also resulted in some enhancement (by 56%) of the stimulation-induced increase in PBF (P < 0.01, n = 6). The increase in PBF was unaffected by infusion of timolol (150 micrograms kg-1) and atropine (1 mg kg-1) but was totally abolished by intravenous pre-treatment with capsaicin (1-3 mg kg-1). The present results suggest that activation of sympathetic nerves exerts inhibitory effects on the afferent nerve-induced vasodilation in the rat incisor pulp unrelated to sympathetic vasoconstriction. |
| Databáze: | OpenAIRE |
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