Effects of blinding and pinealectomy on regional brain monoamine concentrations

Abstract

The effects of blinding with or without pineal ablation on brain monoamine levels were studied in male rats. Brain dopamine (DA), norepinephrine (NE), epinephrine (E), and serotonin (5-HT) were measured by radioenzymatic assays. Four weeks following pinealectomy, E levels were significantly enhanced in the frontal cortex. Chronic blinding decreased striatal DA levels and increased striatal 5-HT levels in both sham-operated and pinealectomized (Px) animals. In a second experiment Px animals were sacrificed 1 or 7 d after pinealectomy in order to examine the short-term effects of pinealectomy. There were no differences between controls and Px animals in their cortical levels of DA, NE, and E and their hippocampal and hypothalamic 5-HT levels. However, the E concentrations measured 1 d after surgery were significantly greater than after 7 d. The implications of these findings with regard to the reported role of the pineal and melatonin in brain homeostasis and endocrine regulation are discussed.

Transcranial AC Pulsed Applications of Weak Electromagnetic Fields Reduces Freezing and Falling in Progressive Supranuclear Palsy: A Case Report

“…Melatonin receptors have been demonstrated in the striatum and brainstem reticular formation (Kopp et d., 1980;Vitte rt a]., 1988;Pazo, 1979;Sallanon et nl., 1982). The effect of EMFs on the secretion of melatonin is relevant to the pathogenesis of PSP since melatonin secretion is diminished in patients with the disease (Vaughan et al, 1979) and also because melatonin regulates midbrain and limbic dopaminergic activity (Anton-Tay et al, 1971;Cotzias et al, 1971;Wendel et al, 1974;Bradbury et 01.. 1985;Burton et al, 1991) as well as noradrenergic and serotonerigic activity (Sugden and Morris, 1979;Niles et al, 1983: Aldegunde et al, 1985Miguez et al, 1991). Furthermore, melatonin is now recognized to exert potent neuroprotective effects by inhibiting oxidative stress and neuronal damage (Barlow-Walden et al, 1995;Giusti et al, 1995;Manev et a/., 1996).…”