Comparison of effects of surgical and chemical sympathectomy on beta adrenergic and muscarinic receptors of parotid gland of young and adult rats.
Surgical (removal of a superior cervical ganglion) or chemical [(administration of a single dose of 6 hydroxydopamine (6 OHDA) (50 mg/kg dose body wt)] sympathectomy of rats at 2 or 8 days of age resulted in an increase in [3H]DHA binding of membranes of parotid gland of young rats (age range 21 days to 48 days). The increase progressed with postnatal age; at 21 days of age (surgical sympathectomy), it was 13%; at 32 days of age with 6 OHDA, it was as much as 34%, but only 26% at 42 days of age with surgical sympathectomy. No change in [3H]QNB binding was observed at any postnatal ages following neonatal sympathectomy. Conversely, surgical sympathectomy of the parotid of adult rat resulted in little or no change in [3H]DHA binding at 1, 2, 3, or 4 weeks postdenervation, but [3H]QNB binding was reduced at all periods, with the reduction from control values at 2 weeks being 34%, and at the subsequent intervals, 24-26%. The increase in number of beta adrenoceptors of the parotid gland was not related to the kind of sympathectomy (chemical or surgical) or neonatal age at which it was done; however, duration of the denervation for 2-3 weeks was necessary for the receptor increase to occur. In the adult, however, the duration of the denervation was of no importance since change in number of beta adrenoceptors did not occur at 1, 2, 3, or 4 weeks after surgical denervation but did occur after only 1 week after of reserpine-induced denervation. QNB binding was decreased with surgical sympathectomy as well as reserpine-induced sympathectomy of adult parotid gland; norepinephrine concentration was decreased to levels of a few percent of innervated glands. The relation between development of glandular supersensitivity and increase in beta adrenoceptors is discussed.
Schneyer
C A
CA
Department of Physiology and Biophysics, University of Alabama, Birmingham 35294.
Humphreys-Beher
M
M
Hall
H D
HD
D000375:Aging; D000818:Animals; D004082:Dihydroalprenolol / Q000378:metabolism; D006892:Hydroxydopamines; D016627:Oxidopamine; D010306:Parotid Gland / Q000378:metabolism*; D011813:Quinuclidinyl Benzilate / Q000378:metabolism; D051381:Rats; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D011976:Receptors, Muscarinic / Q000378:metabolism*; D013562:Sympathectomy; D013563:Sympathectomy, Chemical
D006892:Hydroxydopamines; D011943:Receptors, Adrenergic, beta; D011976:Receptors, Muscarinic; D004082:Dihydroalprenolol; D011813:Quinuclidinyl Benzilate; D016627:Oxidopamine