The Dose—Response Relation in Pharmacology

Tallarida, Ronald J.; Jacob, Leonard S.

doi:10.1007/978-1-4684-6265-4

Cited by 185 publications

(82 citation statements)

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“…6). These curves showed a uniform suppression of the forskolin effect suggestive of non-competitive or physiological antagonism, as defined by Tallarida & Jacob (1979).…”

Section: Suppression Offorskolin-induced Excitationmentioning

confidence: 99%

Purinergic inhibition in the small intestinal myenteric plexus of the guinea‐pig.

Palmer

Wood

Zafirov

1987

The Journal of Physiology

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SUMMARY1. The actions of adenosine on electrical behaviour of myenteric neurones were investigated with intracellular recording methods in guinea-pig small intestine.2. The actions of adenosine were: membrane hyperpolarization, decreased input resistance, enhancement of post-spike hyperpolarizing potentials and suppression of excitability. These effects were observed exclusively in AH/type 2 myenteric neurones.3. The presence of adenosine in the micromolar range of concentrations prevented or suppressed excitatory responses to forskolin. It also aborted the effects of forskolin when added in combination with this activator of adenylate cyclase. 5. The results suggest that the mechanism of the inhibitory action of adenosine is suppression of the catalytic activity of adenylate cyclase and consequent reduction of intraneuronal levels of cyclic AMP.

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“…6). These curves showed a uniform suppression of the forskolin effect suggestive of non-competitive or physiological antagonism, as defined by Tallarida & Jacob (1979).…”

Section: Suppression Offorskolin-induced Excitationmentioning

confidence: 99%

Purinergic inhibition in the small intestinal myenteric plexus of the guinea‐pig.

Palmer

Wood

Zafirov

1987

The Journal of Physiology

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“…Where appropriate the data were subjected to linear regression analysis and 95% confidence limits were calculated as described by Tallarida & Jacobs (1979).…”

Section: Methods Preparation Ofplateletsmentioning

confidence: 99%

Mammalian platelet adrenoceptors

Kerry

Scrutton

Wallis

1984

British J Pharmacology

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1 Mammalian platelets vary widely in their responses to catecholamines in part because these agonists can act via excitatory a-and inhibitory P-adrenoceptors. In the absence of antagonists, adrenaline enhances the response of rabbit platelets to an excitatory agonist, e.g. adenosine-5'-O-(1-thiodiphosphate) (ADP-a-s) acting at another receptor, but has no effect on the response of rat or guinea pig platelets to such an agonist. In the presence of a P-adrenoceptor antagonist, adrenaline enhances the response of rat, but not guinea-pig platelets to ADP-a-S and the extent of the enhanced effect on rabbit platelets is increased. In the presence of an a-adrenoceptor antagonist, adrenaline inhibits the response of rabbit and rat platelets to ADP-a-S but has no such effect on the response of guinea-pig platelets.

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“…For each ADP analogue the weighted mean of the slopes of the pair of lines was used to redraw a pair of parallel lines through the log dose-response curves, and the dose-ratio (DR) was calculated from the shift in these redrawn parallel lines. The pA2 value was calculated from the relationship pA2 = -log (ATP concentration/(DR -1)) All lines were drawn by least squares linear regression analysis, and the calculations were performed by computer according to the method described by Tallarida & Jacob (1979). cyclase (Figure 2).…”

Section: Calculation Ofpa2 Valuesmentioning

confidence: 99%

Competitive Inhibition by Adenosine 5′‐triphosphate of the Actions on Human Platelets of 2‐chloroadenosine 5′‐diphosphate, 2‐azidoadenosine 5′‐diphosphate and 2‐methylthioadenosine 5′‐diphosphate

Cusack

Hourani

1982

British J Pharmacology

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Adenosine 5′‐diphosphate (ADP) induces human platelet aggregation and noncompetitively inhibits stimulated human platelet adenylate cyclase; these two effects are mediated by the same ADP receptor, at which adenosine 5′‐triphosphate (ATP) is a competitive antagonist. Two ADP analogues, 2‐azidoadenosine 5′‐diphosphate (2‐azido‐ADP) and 2‐methylthioadenosine 5′‐diphosphate (2‐methylthio‐ADP) have been reported to be more potent as inhibitors of adenylate cyclase than they are as aggregating agents, but no evidence has been presented that these actions are mediated solely by the ADP receptor. We therefore tested the ability of ATP to inhibit the actions of these compounds and of another ADP analogue, 2‐chloroadenosine 5′‐diphosphate (2‐chloro‐ADP). 2‐Chloro‐ADP, 2‐azido‐ADP and 2‐methylthio‐ADP each induced aggregation and inhibited stimulated adenylate cyclase. Both of these actions were competitively inhibited by ATP (50 μm) with pA2 values similar to those previously found for inhibition by ATP of these effects of ADP. The reported greater potency of 2‐azido‐ADP and of 2‐methylthio‐ADP as inhibitors of adenylate cyclase than as aggregating agents is therefore due only to their greater efficacy for this effect, not to some extra actions elsewhere.

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The Dose—Response Relation in Pharmacology

Cited by 185 publications

References 0 publications

Purinergic inhibition in the small intestinal myenteric plexus of the guinea‐pig.

Purinergic inhibition in the small intestinal myenteric plexus of the guinea‐pig.

Mammalian platelet adrenoceptors

Competitive Inhibition by Adenosine 5′‐triphosphate of the Actions on Human Platelets of 2‐chloroadenosine 5′‐diphosphate, 2‐azidoadenosine 5′‐diphosphate and 2‐methylthioadenosine 5′‐diphosphate

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