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Daily changes in beta-adrenergic sensitivity of rat submandibular gland. Correlation with beta-adrenoceptor rhythm.
- Source :
-
Autonomic neuroscience : basic & clinical [Auton Neurosci] 2001 Jun 20; Vol. 89 (1-2), pp. 1-6. - Publication Year :
- 2001
-
Abstract
- Neurons from the superior cervical ganglia (SCG) innervate the submandibular gland and release noradrenaline during the dark phase of the daily photoperiod. Since in the pineal, another structure innervated by sympathetic neurons, nocturnal activation of the SCG is associated with beta-adrenergic sub- and super-sensitivity rhythms, the possible existence of similar phenomena in the rat submandibular gland was assessed. Wistar female rats, kept on a 14:10 light/dark cycle (light from 06:00 to 20:00 h), were sacrificed at 09:00, 14:00, 20:00, 24:00 and 04:00 h. beta-Adrenoceptors were studied by 3H-dihydroalprenolol binding to membrane preparations. The equilibrium dissociation constant (Kd) did not change as a function of time while significant daily variations in maximal binding values (Bmax) were observed with a peak at 20:00 h. Changes in Bmax correlated with a high response of adenylate cyclase to isoproterenol. In addition, when the response in salivary flow to isoproterenol was measured. a shift to the left (about 1 logarithmic unit) in dose-response curves was observed at 19:00-20:00 has compared to 08:00-09:00 h. These daily variations in isoproterenol responsiveness seem not to depend on the pattern of eating since a 24-h starvation or a nocturnal starvation for 16-18 days did not abolish the morning-evening differences in the salivary flow response to isoproterenol. Rather, the results suggest that the daily variations in isoproterenol response correlate with beta-adrenergic super- and sub-sensitivity phenomena associated with the circadian release of noradrenaline from SCG neurons.
- Subjects :
- Adenylyl Cyclases metabolism
Adrenergic beta-Agonists pharmacology
Adrenergic beta-Antagonists metabolism
Adrenergic beta-Antagonists pharmacology
Animals
Dihydroalprenolol metabolism
Dihydroalprenolol pharmacology
Feeding Behavior physiology
Female
Isoproterenol pharmacology
Rats
Rats, Wistar
Saliva metabolism
Superior Cervical Ganglion physiology
Tritium
Circadian Rhythm physiology
Receptors, Adrenergic, beta metabolism
Submandibular Gland innervation
Submandibular Gland metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1566-0702
- Volume :
- 89
- Issue :
- 1-2
- Database :
- MEDLINE
- Journal :
- Autonomic neuroscience : basic & clinical
- Publication Type :
- Academic Journal
- Accession number :
- 11474637
- Full Text :
- https://doi.org/10.1016/s1566-0702(01)00226-0