An electrophoretic study of proteins secreted by the rat submandibular gland in response to autonomic agonists

Summary Proteins secreted by the rat submandibular gland after administration of autonomic agonists have been fractionated by sodium dodecyl sulphate (SDS) — polyacrylamide gel electrophoresis. α-adrenoceptor, β-adrenoceptor and muscarinic agonists were all found to cause the secretion of different protein populations. This work is supported by a grant from the Cystic Fibrosis Research Trust, made to Dr C.J. Jones, whose help and supervision is gratefully acknowledged.     

Reduction of the quantum content of endplate potentials by atropine

Zusammenfassung Postsynaptische Potentiale der Muskelfasern (EPP) des isolierten Rattenzwerchfells wurden intrazellulär abgeleitet. Die statistische Analyse zeigt, dass der Mengenanteil von EPP bei Anwesenheit von Atropin vermindert ist und zwar simultan mit der postsynaptischen Blockade. Die Erholung des presynaptischen Effektes ist viel langsamer als diejenige des postsynaptischen.

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This work was supported by a grant (to J.I.H.) from the US. National Science Foundation. D.F.W. was a postdoctoral fellow of the US Public Health Service.     

Oxidative phosphorylation and nitrogen fixation by cell-free extracts of the azotobacter

Zusammenfassung Zellfreie Extrakte vonAzotobacter vinelandii O wurden auf ihr Vermögen zur oxydativen Phosphorylierung und Stickstoffixierung untersucht. Obwohl alle Präparate die Fähigkeit zur oxydativen Phosphorylierung besassen und einige davon in der Lage waren Stickstoff zu fixieren, konnte zwischen den beiden Vorgängen — unter den geschilderten experimentellen Bedingungen — keine Abhängigkeit gefunden werden.     

Ecological and evolutionary processes at expanding range margins

Many animals are regarded as relatively sedentary and specialized in marginal parts of their geographical distributions. They are expected to be slow at colonizing new habitats. Despite this, the cool margins of many species' distributions have expanded rapidly in association with recent climate warming. We examined four insect species that have expanded their geographical ranges in Britain over the past 20 years. Here we report that two butterfly species have increased the variety of habitat types that they can colonize, and that two bush cricket species show increased fractions of longer-winged (dispersive) individuals in recently founded populations. Both ecological and evolutionary processes are probably responsible for these changes. Increased habitat breadth and dispersal tendencies have resulted in about 3- to 15-fold increases in expansion rates, allowing these insects to cross habitat disjunctions that would have represented major or complete barriers to dispersal before the expansions started. The emergence of dispersive phenotypes will increase the speed at which species invade new environments, and probably underlies the responses of many species to both past and future climate change.     

Amiloride impairs the cholinergic regulation of potassium permeability in the human sweat gland but not in the rat submandibular gland.

Potassium permeability was monitored in human sweat glands and rat submandibular glands. Acetylcholine increased permeability in both tissues and the responses consisted of transient, calcium-independent and sustained, calcium-dependent components. Amiloride, a drug which inhibits Na(+)-H+ countertransport, impaired the regulation of potassium permeability in sweat glands but not in the submandibular gland. It is suggested that the stimulus-permeability coupling process in the sweat gland may be sensitive to the lowering of internal pH.     

Amiloride impairs the cholinergic regulation of potassium permeability in the human sweat gland but not in the rat submandibular gland

Potassium permeability was monitored in human sweat glands and rat submandibular glands. Acetylcholine increased permeability in both tissues and the responses consisted of transient, calcium-independent and sustained, calcium-dependent components. Amiloride, a drug which inhibits Na⁺?H⁺ countertransport, impaired the regulation of potassium permeability in sweat glands but not in the submandibular gland. It is suggested that the stimulus-permeability coupling process in the sweat gland may be sensitive to the lowering of internal pH.     

Better speech recognition with cochlear implants.

HIGH levels of speech recognition have been achieved with a new sound processing strategy for multielectrode cochlear implants. A cochlear implant system consists of one or more implanted electrodes for direct electrical activation of the auditory nerve, an external speech processor that transforms a microphone input into stimuli for each electrode, and a transcutaneous (rf-link) or percutaneous (direct) connection between the processor and the electrodes. We report here the comparison of the new strategy and a standard clinical processor. The standard compressed analogue (CA) processor presented analogue waveforms simultaneously to all electrodes, whereas the new continuous interleaved sampling (CIS) strategy presented brief pulses to each electrode in a nonoverlapping sequence. Seven experienced implant users, selected for their excellent performance with the CA processor, participated as subjects. The new strategy produced large improvements in the scores of speech reception tests for all subjects. These results have important implications for the treatment of deafness and for minimal representations of speech at the auditory periphery.