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  • Cromakalim  (2)
  • Olfaction  (2)
  • 4,4′-Bi-4H-cyclopenta[def]phenanthrylidene  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Responses of olfactory receptor neurons in Utetheisa ornatrix to gender-specific odors (2000)
    Springer
    Journal of comparative physiology 186 (2000), S. 535-542 
    Details
    ISSN: 1432-1351
    Keywords: Key words Pheromone ; Arctiidae ; Trichoid sensilla ; Electrophysiology ; Olfaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We recorded the electrophysiological responses of individual olfactory receptor neurons in sensilla trichodea on the antennae of adult arctiid moths, Utetheisa ornatrix, to stimulation with volatiles associated with both sexes. All trichoid sensilla contain at least two receptor neurons, each with distinct action potential amplitudes and waveforms, that respond dichotomously to male and female odors. Although, neither female neuron responds to extracts of coremata or the male-produced pheromone hydroxydanaidal, they do respond in a gender-specific manner to the volatiles emanating from whole pupae, hemolymph, thoracic froth, and adult animals of several ages. Thoracic froth, which contains pyrrolizidine alkaloids, is thought to play a role in defense. Froth from moths reared on diets, with or without added pyrrolizidine alkaloids, were equally effective in eliciting gender-specific patterns of response. Male trichoid receptor neurons respond to these same materials with similar patterns of activation. These receptor neurons provide information about substances, which we have termed “gender odors,” that are persistently emitted by nearby animals. These substances do not appear to be the same as those already known to be involved in defense or the sexual dialog between individuals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003590000108
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Sensitivity of Trichoplusia ni (Hübner) pheromone receptor neurons: Relationships between neural thresholds and behavioral responses (1991)
    Springer
    Journal of comparative physiology 168 (1991), S. 739-747 
    Details
    ISSN: 1432-1351
    Keywords: Threshold ; Olfaction ; Insect ; Lepidoptera ; Noctuid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. Responses of Trichoplusia ni HS(A) receptor neurons were measured to determine the minimum detectable concentration (absolute threshold) and the minimum detectable increment (difference threshold) for the major sex pheromone component (Z)-7-dodecen-1-ol acetate (Z7-12∶Ac). The absolute threshold was 1000-fold below the ∼10-11 M level of Z7-12∶Ac at a calling female. The Weber fraction, i.e., the ratio of the difference threshold to the stimulus concentration, declined from ∼0.8 to ∼0.06 as the concentration rose from threshold to high intensities. Relatively smaller fluctuations were detected as the stimulus increased. 2. The HS(A) responses were interpreted in relation to behavior by considering an ideal observer as approximating the central nervous system (CNS). The ideal thresholds were 3–9-fold lower than the HS(A) thresholds. 3. The ideal absolute threshold of the T. ni CNS is comparable to observed behavioral thresholds for wingflutter and taking flight. However, only a low percentage response occurs at threshold. Most males take flight at higher concentrations. Also, the ideal Weber fraction is lower than in most flight-tunnel bioassays. Yet, males respond to small fluctuations in orienting to pheromone plumes. These differences between moths and ideal observers may reflect inhibition at points in the CNS that control the flow of olfactory input.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224362
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Crystal Structure and Molecular Modeling of 4,4′-Bi-4H-cyclopenta[def]phenanthrenylidene and Related Derivatives (2000)
    Springer
    Structural chemistry 11 (2000), S. 245-248 
    Details
    ISSN: 1572-9001
    Keywords: 4,4′-Bi-4H-cyclopenta[def]phenanthrylidene ; oxidative electrocyclization ; Diels-Alder adduct ; pentafulvene ; distorted alkenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The twisted pentafulvene, 4,4′-bi-4H-cyclopenta[def]phenanthrylidene, does not undergo oxidative electrocyclization to a semibuckminsterfullerene under photo-oxidative conditions. However, the use of standard dehydrogenating agents such as DDQ or tetrachloro-2,3-benzoquinone at 200°C resulted in partial oxidative electrocyclization and formation of a Diels–Alder adduct, respectively. The crystal structure of this Diels-Alder adduct was obtained and shown to possess C2 symmetry. The crystal structure for 4,4′-bi-4H-cyclopenta[def]phenanthrylidene was also obtained and the molecular parameters differ slightly from what was previously reported for the same compound. Molecular modeling of this pentafulvene gave a twist angle matching the crystal structure. Similar modeling of related bifluorenylidene, bis-1,1′-indenylidenes and biscyclopentadienylidene gave twist angles which correlate with the computed heats of hydrogenation for the bridging alkene unit.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009262209989
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Comparison of the cromakalim antagonism and bradycardic actions of a series of novel alinidine analogues in the rat (1994)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 350 (1994), S. 158-166 
    Details
    ISSN: 1432-1912
    Keywords: Alinidine ; Bradycardia ; Cromakalim ; Imidazolines ; K+ channels ; K+ channel antagonists ; Rat thoracic aorta ; Rat spontaneously beating right atria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Alinidine, and eight derivatives, were synthesized and tested for their ability to antagonise the actions of the K+ channel opener cromakalim in rat thoracic aorta, and for their ability to induce bradycardia in rat isolated spontaneously beating right atria. Ring segments of rat thoracic aorta were suspended in organ baths to record isometric tension. Tissues were precontracted with K+(20 mM), and full concentration-relaxation curves constructed to cromakalim (0.01–30 μM) in the absence and presence of increasing concentrations of alinidine/derivative. The majority of the compounds tested caused rightward shifts in the cromakalim concentration-effect curves. Rat spontaneously beating right atria were suspended in organ baths to record rate of contraction. Addition of alinidine/derivative caused a concentration-dependent negative chronotropic response. In terms of structure-activity relationships, increasing the length of the N-allyl side-chain on the alinidine molecule (from 3 carbon (3C), to 5 C) resulted in a significant increase in the activity of the compounds as both bradycardic agents and cromakalim antagonists. The most potent compounds in both cases (bradycardic agent and cromakalim antagonist) had no double bond in the side chain. The results suggest that the carbon side-chain influences the activity of alinidine-related compounds both as cromakalim antagonists and as bradycardic agents. However, while similar structure-activity relationships appear to apply for both effects in some instances, there was no significant correlation between the two actions of the alinidine analogues. The results suggest that the ability of alinidine-derivatives to induce bradycardia or to block K+ channels opened by cromakalim can be differentiated on the basis of structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00241091
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Spasmolytic effect of cromakalim in dog coronary artery in vitro (1991)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 343 (1991), S. 519-524 
    Details
    ISSN: 1432-1912
    Keywords: Cromakalim ; K+ channels ; Dog coronary artery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Isometric force development was measured in isolated ring segments of dog left anterior descending coronary artery to K+ (10–70 mM), U-46619 (0.3–30 nM), endothelin-1 (0.1–30 nM), 5-HT (0.1–30 μM) and angiotensin-II (0.1–30 nM), Compared with the maximum tissue response to a K+ depolarizing solution (100%) there was a marked variation in the maximum response to each spasmogen: K+ (111%), U-46619 (85%), endothelin-1 (48%), 5-HT (49%) and angiotensin-II (15%). In arteries pretreated with cromakalim (0.3–10 μM) the maximum response to all constrictor agents (with the exception of K+) was reduced but the potency was unaffected. Maximum responses to angiotensin-II and 5-HT were affected at concentrations approximately threefold lower than those to endothelin-1 and U-46619. Removal of the endothelium increased the maximum response caused by 5-HT and reduced the potency of cromakalim in inhibiting this contraction. Glyceryl trinitrate and sodium nitroprusside were 100–1000 times more potent than cromakalim although they produced qualitatively similar effects. Cromakalim is an effective spasmolytic against a number of vasoconstrictors in the dog coronary artery. No marked spasmogen selectivity could be identified for Comakalim that was not shown by glyceryl trinitrate or sodium nitroprusside.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00169555
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    Paper (German National Licenses)
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