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  • 1
    Electronic Resource
    Electronic Resource
    Effects of maturation on synaptic potentials in the locust flight system (1994)
    Springer
    Journal of comparative physiology 175 (1994), S. 437-447 
    Details
    ISSN: 1432-1351
    Keywords: Insect ; Motor pattern ; Development ; EPSP Synaptic depression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We have measured parameters of identified excitatory postsynaptic potentials from flight interneurons in immature and mature adult locusts (Locusta migratoria) to determine whether parameters change during imaginal maturation. The presynaptic cell was the forewing stretch receptor. The postsynaptic cells were flight interneurons that were filled with Lucifer Yellow and identified by their morphology. Excitatory postsynaptic potentials from different postsynaptic cells had characteristic amplitudes. The amplitude, time to peak, duration at half amplitude and the area above the baseline of excitatory postsynaptic potentials did not change with maturation. The latency from action potentials in the forewing stretch receptor to onset of excitatory postsynaptic potentials decreased significantly with maturation. We suggest this was due to an increase in conduction velocity of the forewing stretch receptor. We also measured morphological parameters of the postsynaptic cells and found that they increased in size with maturation. Growth of the postsynaptic cell should cause excitatory postsynaptic potential amplitude to decrease as a result of a decrease in input resistance, however, this was not the case. Excitatory postsynaptic potentials in immature locusts depress more than in mature locusts at high frequencies of presynaptic action potentials. This difference in frequency sensitivity of the immature excitatory postsynaptic potentials may account in part for maturation of the locust flight rhythm generator.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00199251
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Flight motor patterns of locusts responding to thermal stimuli (1998)
    Springer
    Journal of comparative physiology 183 (1998), S. 477-488 
    Details
    ISSN: 1432-1351
    Keywords: Key wordsLocusta migratoria ; Wing kinematics ; Motor pattern ; Sensorimotor ; Insect flight
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Correctional and intentional steering manoeuvres in locusts differ in several important respects. The most profound difference between the two is the production of large forewing asymmetries in angle of elevation during the downstroke in intentional steering that are not obvious in correctional steering. We investigated the flight motor patterns during intentional steering responses to a radiant heat source. We found asymmetries in the timing of forewing first basalar (m97) activity on the left and right sides that were strongly and positively correlated with forewing asymmetries. Timing asymmetry in the second basalar (m98) and pleuroalar (m85) muscles was not significantly different from the changes observed in m97. The hindwing first basalar (m127) shifted its asymmetry in the opposite direction. The forewing subalar muscle (m99) did not shift its asymmetry with the same magnitude as m97, but instead was phase-shifted relative to m97 on the left and right sides, suggesting its role as a supinator. We conclude that large asymmetries in the elevation angle of the forewings during the downstroke, as are evident in intentional steering, are generated by bulk shifts in the activation times of forewing depressor muscles to cause a relative shift in the time of stroke reversals of the two forewings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003590050273
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Insulin-mediated and glucose-mediated glucose uptake following hemipancreatectomy in healthy human donors (1994)
    Springer
    Diabetologia 37 (1994), S. 1036-1043 
    Details
    ISSN: 1432-0428
    Keywords: Key words Insulin action ; pancreatectomy ; glucose uptake ; pancreas transplantation ; minimal model.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Healthy humans undergoing hemipancreatectomy for the purpose of donation to a family member with IDDM have previously been demonstrated to maintain serum glucose values equal to matched control subjects during short-term glucose infusion despite significant decrements in glucose- and arginine-induced insulin secretion. In order to determine whether humans compensate for hemipancreatectomy by increasing insulin- or glucose-mediated glucose uptake, we measured glucose turnover and insulin sensitivity by three protocols. Insulin-mediated glucose uptake was measured during sequential infusions of insulin at rates of 0.25, 1.0, and 10.0 mU · kg−1· min−1 in 12 donor subjects and 12 matched control subjects maintained at euglycaemia. Both groups displayed similar increases in rates of glucose disappearance and similar decreases in rates of hepatic glucose production. Glucose-mediated uptake was calculated as the difference between the rates of glucose disappearance measured during a hyperglycaemic clamp and a euglycaemic clamp performed at identical rates of insulin infusion and was also found to be similar in both donor subjects and control subjects. Both groups also had indistinguishable measures of insulin sensitivity and glucose effectiveness as determined by the minimal model technique. Therefore, donor subjects appear to compensate for diminished insulin secretion following hemipancreatectomy by an unidentified mechanism since neither insulin- nor glucose-mediated glucose uptake are increased. [Diabetologia (1994) 37: 1036–1043]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00400467
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Insulin-mediated and glucose-mediated glucose uptake following hemipancreatectomy in healthy human donors (1994)
    Springer
    Diabetologia 37 (1994), S. 1036-1043 
    Details
    ISSN: 1432-0428
    Keywords: Insulin action ; pancreatectomy ; glucose uptake ; pancreas transplantation ; minimal model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Healthy humans undergoing hemipancreatectomy for the purpose of donation to a family member with IDDM have previously been demonstrated to maintain serum glucose values equal to matched control subjects during short-term glucose infusion despite significant decrements in glucose- and arginine-induced insulin secretion. In order to determine whether humans compensate for hemipancreatectomy by increasing insulin- or glucose-mediated glucose uptake, we measured glucose turnover and insulin sensitivity by three protocols. Insulin-mediated glucose uptake was measured during sequential infusions of insulin at rates of 0.25, 1.0, and 10.0 mU·kg−1·min−1 in 12 donor subjects and 12 matched control subjects maintained at euglycaemia. Both groups displayed similar increases in rates of glucose disappearance and similar decreases in rates of hepatic glucose production. Glucose-mediated uptake was calculated as the difference between the rates of glucose disappearance measured during a hyperglycaemic clamp and a euglycaemic clamp performed at identical rates of insulin infusion and was also found to be similar in both donor subjects and control subjects. Both groups also had indistinguishable measures of insulin sensitivity and glucose effectiveness as determined by the minimal model technique. Therefore, donor subjects appear to compensate for diminished insulin secretion following hemipancreatectomy by an unidentified mechanism since neither insulin- nor glucose-mediated glucose uptake are increased.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00400467
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
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