Inhibition of dopamine sensitive adenylate cyclase from rat brain striatal homogenates by ascorbic acid¹

Secretion of Newly Taken-Up Ascorbic Acid by Adrenomedullary Chromaffin Cells

“…These observations are characteristic of exocytotic secretion (19, 24). The evidence supporting exocytotic secretion of ascorbate in this report complements the recent data on ascorbate effects on neurotransmitter receptors and Na+,K+-activated adenosine triphosphatase (10)(11)(12)(13) ['4C ascorbate, in the presence or absence of Ca2 , showed that there was an initial high rate of efflux which was independent of the presence of the metal ion. Thereafter, the efflux rate in the presence' of Ca2" was slow; and practically nonexistent after 15 minutes; however, in the absence of Ca2" there was still a significant efflux of the cofactor after 15 minutes and it decreased very slowly.…”

“…However, the role of ascorbate in neuronal function does not appear to be restricted to its participation in dopamine P-hydroxylation. Indeed, recent studies have suggested that ascorbate can modulate neurotransmission, that is, ascorbate was shown to inhibit dopamine-sensitive adenylate cyclase in vitro (10) and to block amphetamine-induced stereotypy in vivo, an action thought to be mediated by dopaminergic neural systems (11). In addition, ascorbate has been shown to inhibit Na+,K+-activated adenosine triphosphatase (12) and the binding of neurotransmitters to their receptors (13).…”

“…In addition to the inhibitory effect of adenosine, we have shown that deoxyadenosine is a "suicide-like" substrate analog that causes the inactivation of purified AdoHcy hydrolase (6), and of AdoHcy hydrolase in ADA-inhibited cultured cells (7). This effect of 2'-deoxyadenosine results in severe deficiency of AdoHcy hydrolase activity in the erythrocytes of ADA-deficient children (8), and in the erythrocytes and lymphoblasts of patients with lymphocytic leukemias when they are treated with the drug 2'-deoxycoformycin, a potent inhibitor of ADA that causes deoxyadenosine accumulation in vivo (9,10).…”

Electrochemical Detection Methods for Monoamine Measurements in Vitro and in Vivo

“…Its real role(s) in neuronal functioning are obscure, but just in the last few years it has been shown to inhibit DA-sensitive adenylate cyclase (Thomas and Zemp, 1977;Tolbert et ai., 1979) and specific binding to neurotransmitter sites (Cox et ai., 1980;Kayaalp and Neff, 1980;Leslie et ai., 1980). It also stimulates the release of ACh and, to a lesser extent, NE from synaptic vesicles (Kuo et ai., 1979).…”

Inhibition of the Soluble Form of Testis Adenylate Cyclase by Catechol Estrogens and Other Catechols

“…Ascorbic acid, commonly used as antioxidant, has been shown to have deleterious effect on dopaminergic (22,23), adrenergic (24), and opioid receptors (25) in membrane preparations. It was therefore of interest to ascertain whether ascorbate at concentrations routinely employed in in vitro incubation studies would affect interaction of catechol-related compounds with the testis enzyme.…”