The effects of diltiazem on Periplaneta americana

The effects of the calcium antagonist diltiazem on nerve and muscle in the cockroach Periplaneta americana were examined. Diltiazem was observed to inhibit myogenic and glutamate-induced contractions of the visceral muscle while having either a potentiating, an inhibiting or a biphasic effect against proctolin-induced contractions. Against the isolated nervous system, diltiazem induced an increase in spontaneous discharge activity, followed by nerve block. Injection of diltiazem into cockroaches produced behavioral and toxic effects.     

Toxicity of benzenethiol and its derivatives onMusca domestica (DDT-resistant strain) and onPeriplaneta americana

Riassunto Gli autori hanno studiato la tossicità del tiofenolo a di alcuni suoi derivati per gli insetti. Il tiofenolo si è rivelato notevolmente tossico sia perPeriplaneta americana che perMusca domestica (ceppo resistente al DDT), mentre la maggior parte dei suoi derivati è fornita di scarsa tossicità.     

Structure of the foregut cuticle ofPeriplaneta americana

Summary The cuticular lining of the foregut ofPeriplaneta americana did not contain either pore canals or the openings of dermal glands, and the length of the cuticular spines decreased posteriorwards.I am grateful to ProfessorR. Rakshpal, Head, Department of Zoology for supervizing my work and to University Grants Commission, India, for awarding a Junior Research Fellowship.     

The perception of vibration by the subgenual organ inZootermopsis angusticollis Emerson andPeriplaneta americana L.

Zusammenfassung Aus den Ergebnissen einer elektrophysiologischen Untersuchung des Subgenualorgans zweier Insekten lässt sich ableiten, dass eine Erregung der Sensillen nur nach einer plötzlichen Störung des Beines aus der Ruhe oder dem Gleichgewichtszustand auftritt.Es wird angenommen, dass eine plötzliche Verlagerung der Stiftzellen und der distalen akzessorischen Zellen des Subgenualorgans aus der Ruhe oder dem Gleichgewichtszustand sie während einer sehr kurzen Periode in Eigenschwingung versetzt. In Abhängigkeit von ihrem Bau dürfte die Frequenz der Eigenschwingung bei jeder der zwei Zellengruppen verschieden sein. Infolgedessen wird es, bis zur Einstellung eines neuen Gleichgewichtszustandes, zu einer schnellen Veränderung der Kräfte an der Verbindung zwischen Stiftzellen und akzessorischen Zellen kommen, was Nervenimpulse auslösen könnte.     

Rhythmicity of aminotransferase in the cockroach,Periplaneta americana

Summary Aspartate (AAT) and alanine aminotransferase (AIAT) activities in nervous system and coxal leg muscle of the cockroach showed circadian variations with maximal activity around midnight, alternating with minimal activity at 12.00 noon of the solar day. The enhanced activity levels of the enzymes observed during night dark hours may be related to higher energy requirements during increased locomotor activity of the animals.We thank Prof. K. S. Swami, for providing facilities. The financial help rendered by UGC and CSIR, in the form of Junior (to SV) and Senior (to TPK) Research Fellowships is acknowledged.     

A study on the parameters of digestion inPeriplaneta americana L

Summary An attempt was made to provide evidence for the regulatory mechanism for digestion inPeriplaneta americana by studying possible correlations between digestive enzymes, taking midgut protease activity into considerationI wish to acknowledge Prof. J. Bahadur, Jiwaji University, Gwalior, India, for his supervision, criticism and encouragement during the course of this study. Award of Junior Research Fellowship by C.S.I.R., New Delhi is also thankfully acknowledged.     

Frontal ganglion and water balance inPeriplaneta americana L.

Zusammenfassung Der Gewichtsverlust bei frontalganglionektomierten Schaben innerhalb von 24 h im Exsikkator ist wesentlich grösser als derjenige bei scheinoperierten Tieren. Er erreicht Werte, wie sie bei toten Tieren auftreten. Der Gewichtsverlust ist mit einer signifikanten Zunahme der Gefrierpunktserniedrigung in der Hämolymphe verbunden. Durchtrennung beider Frontalkonnektive hat dieselbe Wirkung wie Ganglionektomie.     

Distribution of repetitive DNA sequences in the polytene chromosomes ofRhynchosciara americana

Summary The distribution of fast, intermediate and slow renaturing fractions ofRhynchosciara americana DNA was examined in the polytene salivary gland chromosomes by in situ hybridization. Heterochromatic areas readily hybridized but hybrid formation in the euchromatin depended more on the repetitiveness of the RNA probe.Supported by funds from the Fundação de Amparo à Pesquisa do Estado de São Paulo (Projecto BIOQ-FAPESP) and from The Research Foundation of The City University of New York.R.A. Eckhardt was a visiting professor under the Multinational Scientific and Technological Development Program of the Organization of American States.     

Defensive steroids from a carrion beetle (Silpha americana)

Summary The defensive anal effluent discharged bySilpha americana in response to disturbance contains a mixture of steroids stemming from a glandular annex of the rectum. The compounds have been characterized as 15-hydroxyprogesterone (1, principal component), 5-pregnan-15-ol-3, 20-dione (2), 5-pregnan-3, 15-diol-20-one (3), 5-pregnan-7, 15-diol-3,20-dione (4), 5-pregnan-3, 7, 15-triol-20-one (5), 5-pregnan-16-ol-3,20-dione (6), and 5-pregnan-3, 16-diol-20-one (7), none previously found in insects. Bioassays with jumping spiders showed compounds1 and6 to be feeding deterrents at the 1 g level.Paper No. 78 of the series: Defense Mechanisms of Arthropods. Study supported by NIH (Grants AI-02908, AI-12020). We thank Maura Malarcher and Maria Eisner for excellent technical help, and the Squibb Institute of Medical Research for samples of authentic reference compounds.     

Defensive steroids from a carrion beetle (Silpha americana)

The defensive anal effluent discharged by Silpha americana in response to disturbance contains a mixture of steroids stemming from a glandular annex of the rectum. The compounds have been characterized as 15 beta-hydroxyprogesterone (1, principal component), 5 beta-pregnan-15 beta-ol-3,20-dione (2), 5 beta-pregnan-3 alpha, 15 beta-diol-20-one (3), 5 beta-pregnan-7 beta, 15 beta-diol-3,20-dione (4), 5 beta-pregnan-3 alpha, 7 beta, 15 beta-triol-20-one (5), 5 beta-pregnan-16 alpha-ol-3,20-dione (6), and 5 beta-pregnan-3 alpha, 16 alpha-diol-20-one (7), none previously found in insects. Bioassays with jumping spiders showed compounds 1 and 6 to be feeding deterrents at the 1 microgram level.     

Thermal acclimatory responses of salivary amylase of Periplaneta americana (Linn.)

Summary A differential thermal acclimatory response of salivary amylase is evident in P. americana-nymphs demonstrating a translational and males a rotational pattern, while females exhibit the translational cum rotational pattern (Prosser's type IV-D).     

Influence of recurrent nerve severance on haemolymph proteins inPeriplaneta americana L.

Zusammenfassung Es wird gezeigt, dass bei der weiblichen SchabePeriplaneta americana Durchtrennung des Nervus recurrens zu einer Reduktion der Hämolymphproteine führt.     

Absorption and excretion of benzpyrene in the cockroach (Periplaneta americana)

Résumé Le benzopyrène le pyrène et l'anthracène peuvent être révélés au moyen du spectrophotomètre dans les extraits de tissu des blattes (Periplaneta americana) nourries avec ces hydrocarbures; ils sont excrétés lorsqu'on interrompt l'alimentation.

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Supported by grant CA 01469-11 from the National Cancer Institute, Public Health Service.     

Nerve growth in cockroaches (Periplaneta americana) with rotated ganglia

Summary The axons of motorneurons in rotated cockroach ganglia grow into the limb opposite the one they normally innervate and appear to synapse with appropriate muscles. Apparently the classification of motorneurons is duplicated about the mid-line.I thankNan Cowan for her expert technical assistance.     

Distribution of repetitive DNA sequences in the polytene chromosomes of Rhynchosciara americana.

The distribution of fast, intermediate and slow renaturing fractions of Rhynchosciara americana DNA was examined in the polytene salivary gland chromosomes by in situ hybridization. Heterochromatic areas readily hybridized but hybrid formation in the euchromatin depended more on the repetitiveness of the RNA probe.     

Interaction of diltiazem with propranolol on atrioventricular conduction and refractoriness in the dog

Summary Propranolol pretreatment (0.1 mg·kg^–1) significantly increased the lengthening induced by diltiazem (0.15 mg·kg^–1+0.01 mg·kg^–1·min^–1, 20 min) of the A-H interval of His bundle potential recordings in the dog. In the presence of propranolol, diltiazem also significantly increased the atrioventricular effective refractory period. The results suggest the possible occurrence of AV blocks as a result of the use of a diltiazem-beta blocker combination in clinical practice.Acknowledgments. Financial support from the U.E.R. Biologie Humaine is gratefully acknowledged.     

Neurosecretory control of Corpora allata activity in cockroach,Periplaneta americana L.

Summary The brain neurosecretory material is involved in the control of Corpora allata activity during post-embryonic development. A high concentration of neurosecretory material within the Corpora allata restrains the activity of the gland.