Effects of ergots on adenylate cyclase activity in the corpus striatum and pituitary

Schmidt, Michael; Hill, Leo E.

doi:10.1016/0024-3205(77)90028-5

Cited by 96 publications

(21 citation statements)

References 30 publications

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“…Pituitary recognition sites for dopamine have been termed D-2, to differentiate them from the D-1 recognition sites, which are located in various brain regions and in parathyroids and are coupled to adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] (5). Whether or not D-2 dopamine recognition sites are entirely dissociated from adenylate cyclase is still controversial: some reports suggest that occupancy of pituitary recognition sites for dopamine inhibits adenylate cyclase (6), others claim that this occupancy stimulates the enzyme (7), while still others claim that stimulation of D-2 dopamine sites fails to change adenylate cyclase (8)(9)(10). Thus, while pharmacological criteria support the distinction between two classes of dopamine recognition sites (5), it is not yet clear what is the biochemical marker of the D-2 sites.…”

mentioning

confidence: 99%

Dopaminergic modulation of adenylate cyclase stimulation by vasoactive intestinal peptide in anterior pituitary.

Onali¹,

Schwartz²,

Costa³

1981

Proc. Natl. Acad. Sci. U.S.A.

105

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mentioning

confidence: 99%

Dopaminergic modulation of adenylate cyclase stimulation by vasoactive intestinal peptide in anterior pituitary.

Onali¹,

Schwartz²,

Costa³

1981

Proc. Natl. Acad. Sci. U.S.A.

105

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“…Neither lergotrile nor bromocriptine stimulate striatal dopamine sensitive adenylate cyclase in vitro (Trabucchi, Spano, Tonon & Frattola, 1976;Schmidt & Hill, 1977;Kebabian, Calne & Kebabian, 1977); instead, both ergot derivatives antagonize the activation of this enzyme elicited by dopamine (Kebabian, ClementCormier, Petzold & Greengard, 1975). Similarly, lergotrile and bromocriptine, even in doses 1000 times the minimal effective dose of dopamine, do not produce renal vasodilatation in the in vivo canine model (Volkman & Goldberg, 1976).…”

Section: Discussionmentioning

confidence: 99%

Cross tolerance between two dopaminergic ergot derivatives‐ bromocriptine and lergotrile.

Teychenne¹,

Rosin²,

Plotkin³

et al. 1980

Brit J Clinical Pharma

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1 When initially given to patients with idiopathic parkinsonism, lergotrile induced marked supine arterial hypotension. Tolerance to this hypotensive effect developed and larger doses of lergotrile were administered without this adverse effect. 2 Cross tolerance occurred between lergotrile and a structurally related ergot derivative, bromocriptine. A high dose of lergotrile given to patients who had been on long term bromocriptine therapy did not induce any significant hypotension when compared to placebo whereas hypotension still occurred when lergotrile was given after previous treatment with levodopa.

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“…Apomorphine does mimic to a lesser extent, the effect of dopamine and, at same time acts as a dopamine agonist on adenylate cyclase in striatal homogenate (6,15 free preparations of the rat striatum (13,(25)(26)(27). Conversely, lergotrile introduced as a dopaminergic agonist was later reported not to stimulate the enzyme in the striatal homo genate (13,14). Other ergots such as ergonovine, ergocristine and elymoclavine slightly stimulate the striatal enzyme (13,17), whereas only LSD and ergometrine out of 8 ergot derivatives including lisuride and bromocriptine exhibited weak stimulant properties (23).…”

Section: Discussionmentioning

confidence: 99%

“…Conversely, lergotrile introduced as a dopaminergic agonist was later reported not to stimulate the enzyme in the striatal homo genate (13,14). Other ergots such as ergonovine, ergocristine and elymoclavine slightly stimulate the striatal enzyme (13,17), whereas only LSD and ergometrine out of 8 ergot derivatives including lisuride and bromocriptine exhibited weak stimulant properties (23).…”

Section: Discussionmentioning

confidence: 99%

“…Despite potent dopaminergic activities in vivo, however, dopaminergic ergots such as lisuride (12) and lergotrile (13,14) are apparently devoid of stimulatory action on adenylate cyclase in striatal homogenates, although these ergots were found to inhibit dopamine-dependent stimulation of the enzyme. Based on these observations, it is generally assumed that stimulatory mechanisms of some ergots on the dopamine receptors may differ from that of apomorphine in which adenylate cyclase is involved (15).…”

mentioning

confidence: 99%

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Stimulatory Action of Lisuride on Dopamine-Sensitive Adenylate Cyclase in the Rat Striatal Homogenate

Azuma¹,

Oshino²

1980

Japanese Journal of Pharmacology

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Abstract-Effect of lisuride, an ergot derivative of isolysergic structure, on dopamine sensitive adenylate cyclase was studied in the homogenate of rat corpus striatum. Stimulatory action of lisuride, similar to the actions of dopamine and apomorphine, on striatal adenylate cyclase was potentiated significantly by guanosine triphosphate (GTP) and by guanyl-5'-yl imidodiphosphate (GMP-PNP), although with lisuride alone, there was only a slight stimulation.The maximal stimulation attained in the presence of GTP corresponded to about 1.4 times the basal rate of cyclic AMP formation in the homogenate and was abolished by an addition of haloperidol.Lisuride at a concentration above 3 ,uM inhibited stimulation of cyclic AMP formation by dopamine. The effect of lisuride and the extent of potentiation by the guanyl nucleotides were almost comparable to the effects of apomorphine, under corresponding conditions. Thus, lisuride, like apomorphine, acts as a partial agonist-antagonist, and has the ability to stimulate the dopamine-sensitive adenylate cyclase in the rat corpus striatum.Drugs such as apomorphine stimulate dopaminergic receptors in the brain. Lisuride, a semi-synthetic ergot derivative of isolysergic structure (1), also exhibits potent dopaminergic actions in vivo, as demonstrated by enhancement of locomotor activity (2), induction of stereotyped behavior (2) and reduction in serum prolactin levels (3). Direct stimulatory action of lisuride on dopamine receptors of post synaptic membrane was suggested by the finding that the induction of stereotyped behavior was inhibited by haloperidol, a blocker of dopamine receptors, and not by a-methyl-p-tyrosine methyl ester, an inhibitor of dopamine synthesis (2). It was also reported that specific binding of 3H-spiroperidol and of 3H-lisuride was inhibited by lisuride (4) and (+)-butaclamol (5), respectively.Adenylate cyclase in some regions of the brain is stimulated by dopamine in vitro (6-8), hence, the possibility that adenylate cyclase plays an important role in the post synaptic membrane has been discussed in relation to dopamine-dependent brain functions (9, 10).In fact, after solubilization of the synaptic membrane of bovine caudate nuclei, the enzyme activity of dopamine-sensitive adenylate cyclase could be reconstituted with two protein fractions, the one necessary for dopamine binding and the other for the catalytic site (11).Though less efficient than dopamine, apomorphine does stimulate the adenylate cyclase

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Effects of ergots on adenylate cyclase activity in the corpus striatum and pituitary

Cited by 96 publications

References 30 publications

Dopaminergic modulation of adenylate cyclase stimulation by vasoactive intestinal peptide in anterior pituitary.

Dopaminergic modulation of adenylate cyclase stimulation by vasoactive intestinal peptide in anterior pituitary.

Cross tolerance between two dopaminergic ergot derivatives‐ bromocriptine and lergotrile.

Stimulatory Action of Lisuride on Dopamine-Sensitive Adenylate Cyclase in the Rat Striatal Homogenate

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