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The development and properties of two-site ("sandwich") enzyme immunoassays for gluten in foods, based on monoclonal antibodies to heat-stable u-gliadins and related prolamins from wheat, rye, and barley, are described. The complete assay requires under 2 h when precoated microwells are used. The effects of altering component antibodies, gluten extraction conditions, and solvent on assay performance are described. Quantitative results were obtained by using a simple one-step extraction procedure with 40% ethanol over a very wide range of gluten contents (0.015-10%). The method was developed for the quantitative analysis of gluten in virtually all types of foods, whether raw, cooked, or processed.

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SUMMARY1. Adenosine and several of its analogues produced a concentration-dependent shortening of calcium-dependent action potential (c.a.p.) duration of mouse dorsal root ganglion (d.r.g.) neurones in dissociated cell culture. The following rank order of potency was obtained: N6-(L-phenylisopropyl)adenosine > N6-(D-phenylisopropyl)adenosine > N6-cyclohexyladenosine > 2-chloroadenosine > 1-methylisoguanosine > adenosine. Effects of adenosine agonists on c.a.p. duration were blocked by methylxanthine adenosine antagonists. Adenosine monophosphate (AMP) and cyclic AMP shortened c.a.p.s in d.r.g. neurones, while ATP also depolarized cells.2. Voltage-clamp analysis revealed that the effect arose from reduction of a voltage-dependent calcium conductance. Adenosine agonists reduced depolarizationevoked inward currents but did not alter membrane conductance following blockade of calcium channels by cadmium. Additionally, adenosine reduced the instantaneous current-voltage slope (chord conductance) during step commands that produced maximal activation of voltage-dependent calcium conductance.3. If effects of adenosine on neuronal somata and synaptic terminals are similar, adenosine agonists may inhibit neurotransmitter release in the central nervous system by inhibiting a voltage-dependent calcium conductance. Since effects of adenosine agonists did not correspond with their relative potencies as modulators of adenylate cyclase activity or inhibitors of neurotransmitter release in peripheral tissues, a novel adenosine receptor may be involved in regulation of this conductance.