TY - JOUR
T1 - Adrenergic receptor systems and unscheduled DNA synthesis in the rat brain
AU - Sadile, A. G.
AU - Lamberti-D'Mello, C.
AU - Cerbone, A.
AU - Amoroso, S.
AU - Annunziato, L.
AU - Menna, T.
AU - Buono, C.
AU - Giuditta, A.
PY - 1995
Y1 - 1995
N2 - Two experiments were carried out in the albino rat to investigate the role of brain adrenergic systems in DNA remodeling. Adult maw Sprague-Dawley rats were given an intraventricular micreoinjection of an adronergic drug or vehicle followed 2 h later by the intraventricular injection of 50 μCi of [3H-methyl]tinymkline. The rats were sacrificed 0.5 h after the injection of the radioactive tracer. The rate of DNA synthesis was determined by measuring the amount of radioactive precursor incorporated into the DNA extracted from homogenates of several brain areas. In Experiment 1, at time 0 rats received the alpha-adrenergic antagonist phentolamine (5 μg), the beta antagonist propranolol (10 μg), the alpha agonist phenylephrine (1 μg), the beta agonist isoproterenol (12.5 μg), or the vehicle. The latter decreased UBDS in neocortex, and increased it in the septum, neostriaturn, hypothalamus, cerebellum, and rest of the brain. The alpha and beta agonists and antagonists induced several significant effects, depending on the brain region. In Experiment 2, rats were bilateraly lesioned in the dorsal noradrenergic bundle (DNB) by injection or 8-hydroxydopamine or were sham lesioned. One week later, at time 0 they were given the alpha agonist phenylephrine (1 μg), the beta agonist isoproterenol (12.5 μg), or the vehicle. The DNB-lesionsd rats showed a higher UBDS in the hippocampus, neocortex, and hypothalamus, which was reversed by the alpha or time beta agonist The results suggest an influence of the DNB, probably as a tonic Inhibitor of UBDS in time hippocampus and the hypothalamus which, in turn, are likely to be mediated by beta- and alpha-adrenergic receptors. In addition, a phasic inhibitory effect seems to be mediated by beta and alpha receptors in the neocortex, and by beta receptors in the cerebellum. A modulatory role of central adrenergic systems on unscheduled brain DNA synthesis may be inferred from these findings.
AB - Two experiments were carried out in the albino rat to investigate the role of brain adrenergic systems in DNA remodeling. Adult maw Sprague-Dawley rats were given an intraventricular micreoinjection of an adronergic drug or vehicle followed 2 h later by the intraventricular injection of 50 μCi of [3H-methyl]tinymkline. The rats were sacrificed 0.5 h after the injection of the radioactive tracer. The rate of DNA synthesis was determined by measuring the amount of radioactive precursor incorporated into the DNA extracted from homogenates of several brain areas. In Experiment 1, at time 0 rats received the alpha-adrenergic antagonist phentolamine (5 μg), the beta antagonist propranolol (10 μg), the alpha agonist phenylephrine (1 μg), the beta agonist isoproterenol (12.5 μg), or the vehicle. The latter decreased UBDS in neocortex, and increased it in the septum, neostriaturn, hypothalamus, cerebellum, and rest of the brain. The alpha and beta agonists and antagonists induced several significant effects, depending on the brain region. In Experiment 2, rats were bilateraly lesioned in the dorsal noradrenergic bundle (DNB) by injection or 8-hydroxydopamine or were sham lesioned. One week later, at time 0 they were given the alpha agonist phenylephrine (1 μg), the beta agonist isoproterenol (12.5 μg), or the vehicle. The DNB-lesionsd rats showed a higher UBDS in the hippocampus, neocortex, and hypothalamus, which was reversed by the alpha or time beta agonist The results suggest an influence of the DNB, probably as a tonic Inhibitor of UBDS in time hippocampus and the hypothalamus which, in turn, are likely to be mediated by beta- and alpha-adrenergic receptors. In addition, a phasic inhibitory effect seems to be mediated by beta and alpha receptors in the neocortex, and by beta receptors in the cerebellum. A modulatory role of central adrenergic systems on unscheduled brain DNA synthesis may be inferred from these findings.
KW - 6-Hydroxydopamine
KW - H-Thymidine incorporation
KW - Alpha- and beta-Adrenergic receptors
KW - Deoxyribonucleic acid
KW - Dorsal noradrenergic bundle
KW - Isoproterenol
KW - Phentolamine
KW - Phenylephrine
KW - Propranolol
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U2 - 10.1016/0361-9230(94)00267-5
DO - 10.1016/0361-9230(94)00267-5
M3 - Article
C2 - 7606489
AN - SCOPUS:0028917112
VL - 37
SP - 139
EP - 148
JO - Brain Research Bulletin
JF - Brain Research Bulletin
SN - 0361-9230
IS - 2
ER -