Effects of some sympathomimetic amines on the response of the rabbit isolated ear artery to noradrenaline and electrical stimulation

1968 ◽  
Vol 20 (4) ◽  
pp. 314-315
Author(s):  
G. A. Bentley ◽  
A. H. M. Hussain
Keyword(s):  
Electrical Stimulation ◽  
Sympathomimetic Amines ◽  
Ear Artery

Responses to electrical stimulation, noradrenaline, serotonin, and vasopressin in the isolated ear artery of the developing lamb and ewe

1977 ◽  
Vol 55 (5) ◽  
pp. 1001-1006 ◽  
Author(s):  
D. G. Wyse ◽  
G. R. Van Petten ◽  
W. H. Harris
Keyword(s):  
Electrical Stimulation ◽  
Post Partum ◽  
Adrenergic Innervation ◽  
Threshold Concentration ◽  
Maximal Response ◽  
Adult Tissue ◽  
Adrenergic Neurons ◽  
Lysine Vasopressin ◽  
Ear Artery ◽  
Stimulation Of

Responses of isolated helical strips of ovine ear artery to electrical stimulation of postganglionic adrenergic neurons and exogenous agonists were studied at various stages of development from 110 days of gestation through to adulthood. Only rudimentary responses were observed at 110–115 days of gestation. A parallel development of responses to noradrenaline (NA), serotonin, and lysine vasopressin began sometime after 110–115 days of gestation and continued until 133–137 days of gestation but there was little development of the latter responses until more than 3–5 days post partum. Development of responses to exogenous agonists was incomplete 2–3 weeks post partum. The development of postganglionic adrenergic responses lagged behind those to exogenous NA. Two to three weeks post partum the NA maximal response was one-third that of adult tissue whereas the response to 16 Hz (highest frequency used) was one-sixth that of adult tissue. The NA threshold concentration was lower in arterial strips of adult animals than it was in those of younger animals. The data suggest that development of functional postganglionic adrenergic innervation of vascular smooth muscle begins late in gestation and continues well after birth; this development is preceded by development of vascular mechanisms involved in the response to several agonists.

The Effect of Cocaine, Reserpine, and 6-Hydroxydopamine on the Response of the Perfused Central Artery of the Rabbit Ear to Sympathomimetic amines

1975 ◽  
Vol 53 (1) ◽  
pp. 38-46 ◽  
Author(s):  
Man Sen Yong ◽  
Pi-Chuan Chen
Keyword(s):  
Nerve Endings ◽  
Adrenergic Nerve ◽  
Sympathomimetic Amines ◽  
Central Artery ◽  
Ear Artery ◽  
Rabbit Ear ◽  
Uptake Process ◽  
Adrenergic Nerve Endings ◽  
The Difference ◽  
6 Hydroxydopamine

The perfused central artery of the rabbit ear was less sensitive to extraluminal than to intraluminal noradrenaline, but the reverse was true for metaraminol, methoxamine, metanephrine, and isoproterenol. No difference was noted between the extraluminal and intraluminal potency of phenylephrine. Cocaine potentiated the effect of extraluminal and intraluminal noradrenaline, but decreased that of intraluminal phenylephrine. Irrespective of the route of administration, the constrictor potencies of other sympathomimetic amines were not affected by cocaine. Arteries of reserpine-treated rabbits were supersensitive to extraluminally and intraluminally applied noradrenaline and phenylephrine, but they were not supersensitive to metaraminol. 6-Hydroxydopamine effectively destroyed adrenergic nerve endings of the central ear artery and increased its responses to both extraluminal and intraluminal noradrenaline and phenylephrine. However, only the constrictor potencies of intraluminally applied metaraminol and methoxamine were enhanced by 6-hydroxydopamine. The apparent discrepancies between the results obtained by various procedures that eliminate or impair the nerve uptake process suggest that the difference in the constrictor potency of extraluminal and intraluminal sympathomimetic amines is probably unrelated to their uptake by nerves located in the adventitio–medial junction of the artery.

The “KIMWIPE” Effect in Ultra-Thin Cryosections

1985 ◽  
Vol 43 ◽  
pp. 458-459
Author(s):  
I. Taylor ◽  
P. Ingram ◽  
J.R. Sommer
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Muscle Fibers ◽  
Ice Crystals ◽  
Crystal Formation ◽  
Ice Crystal ◽  
Thin Sections ◽  
Skeletal Muscle Fibers ◽  
Freeze Dried ◽  
Ice Crystal Formation

In studying quick-frozen single intact skeletal muscle fibers for structural and microchemical alterations that occur milliseconds, and fractions thereof, after electrical stimulation, we have developed a method to compare, directly, ice crystal formation in freeze-substituted thin sections adjacent to all, and beneath the last, freeze-dried cryosections. We have observed images in the cryosections that to our knowledge have not been published heretofore (Figs.1-4). The main features are that isolated, sometimes large regions of the sections appear hazy and have much less contrast than adjacent regions. Sometimes within the hazy regions there are smaller areas that appear crinkled and have much more contrast. We have also observed that while the hazy areas remain still, the regions of higher contrast visibly contract in the beam, often causing tears in the sections that are clearly not caused by ice crystals (Fig.3, arrows).

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