John William Daly

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The diterpene, forskolin [half-maximal effective concentration (EC50), 5-10 microM] activates adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] in rat cerebral cortical membranes in a rapid and reversible manner. Activation is not dependent on exogenous guanyl nucleotides and is not inhibited by guanosine 5'-O-(2-thiodiphosphate) when(More)
A diverse array of biologically active, lipid-soluble alkaloids have been discovered in amphibian skin. Such alkaloids include the following: the steroidal samandarines from salamanders, the batrachotoxins, histrionicotoxins, gephyrotoxins, and epibatidine from neotropical poison frogs (Dendrobatidae), the pumiliotoxins, allopumiliotoxins,(More)
A small Neotropical frog, Dendrobates pumilio, undergoes interpopulational variation in color, degree of toxicity, size, and habits. Differences in body coloration encompass the visible spectrum from red to blue, as well as achromatic black and white. There are wide variations in the degree of toxicity, but these variations are not correlated with supposed(More)
Cutaneous granular glands are a shared character of adult amphibians, including caecilians, and are thought to be the source of most biologically active compounds in amphibian skin. Data are available from one or more species in over 100 of nearly 400 genera comprising the three living orders of Amphibia. Many species contain unidentified substances judged(More)
Central stimulant actions of 10 methylxanthines in mice correlate with affinities for adenosine receptors labeled with N6-[3H]cyclohexyladenosine. Affinities of methylxanthines for adenosine receptors are consonant with central levels attained at behaviorally effective doses. The much higher concentrations of methylxanthines required to influence(More)
A total of 232 alkaloids, representing 21 structural classes were detected in skin extracts from the dendrobatid poison frog Oophaga pumilio, collected from 53 different populations from over 30 years of research. The highly toxic pumiliotoxins and allopumiliotoxins, along with 5,8-disubstitiuted and 5,6,8-trisubstituted indolizidines, all of which are(More)
Australian myobatrachid frogs of the genus Pseudophryne have only two classes of alkaloids in skin extracts, pseudophrynamines (PSs) and pumiliotoxins (PTXs). The former are unique to such Australian frogs, while the PTXs occur worldwide in all other genera of frogs/toads that contain lipophilic alkaloids. The major alkaloid of wild-caught frogs from one(More)
Caffeine has both positive effects that contribute to widespread consumption of caffeine-containing beverages and adverse unpleasant effects if doses are increased. Caffeine has weak reinforcing properties, but with little or no evidence for upward dose adjustment, possibly because of the adverse effects of higher doses. Withdrawal symptoms, although(More)