The response of the circular muscle layer of the guinea-pig isolated vas deferens to transmural electrical stimulation
| Autor: | A.T. Birmingham, Mary D. Anstey |
|---|---|
| Rok vydání: | 1978 |
| Předmět: |
Guanethidine
Male Moxisylyte Guinea Pigs Stimulation Tetrodotoxin In Vitro Techniques chemistry.chemical_compound Procaine Norepinephrine Vas Deferens medicine Animals Anesthetics Local Bethanidine Pharmacology Vas deferens Muscle Smooth Anatomy Electric Stimulation Perfusion medicine.anatomical_structure chemistry Papers Biophysics medicine.symptom medicine.drug Muscle contraction Muscle Contraction |
| Zdroj: | British journal of pharmacology. 63(4) |
| ISSN: | 0007-1188 |
| Popis: | 1 Four preparations are described for the isolation of the response of the circular muscle of the guinea-pig vas deferens. These are the `Furchgott' strip, the `Vane' strip, the chain preparation and the perfused preparation. 2 The four preparations were stimulated transmurally with pulses of supramaximal voltage. The threshold pulse width to which the strips and the perfused preparation responded was 0.025 ms and the maximum responses occurred at 0.1 ms. The threshold frequency was 2 Hz for strip and perfused preparations, the maxima being 20 or 50 Hz for strip preparations and 100 Hz for perfused preparations. The effect of varying the number of pulses per train was also investigated on the perfused vas. Responses occurred to train lengths of 8, 16, 32, 128 pulses, the maximum response being given at 128 pulses at 100 Hz; 256 pulses per train did not produce a further increase in response. The perfused preparation exhibited an after-response at certain frequencies and train lengths. 3 Tetrodotoxin and the local anaesthetics, procaine and lignocaine, reversibly abolished the responses of strip and perfused preparations to transmural stimulation. 4 The response to intramural nerve fibre stimulation was abolished by guanethidine or bethanidine; this abolition was reversed by dexamphetamine. Noradrenaline contracted strip preparations of circular muscle and raised the pressure in perfused preparations; noradrenaline was competitively antagonized by thymoxamine. The major part of the motor innervation of the circular layer seems to be noradrenergic. |
| Databáze: | OpenAIRE |
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