Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.795914
Title: Some factors that affect calcium-sensitivity in the rat tail artery
Author: Ugwu, Andrew Chukwuma
Awarding Body: University of Glasgow
Current Institution: University of Glasgow
Date of Award: 1987
Availability of Full Text:
Access from EThOS:
Access from Institution:
Abstract:
The calcium sensitivity of noradrenaline (NA) and potassium chloride (KCl)-induced contractions of vascular smooth muscle were investigated in calcium readdition experiments under different oxygen tensions and temperatures in the isolated perfused rat tail artery (male Wistar, 300-350g). We started by establishing the most favourable conditions for responses of the smooth muscle in the preparation, and making an extensive analysis of the influence of experimental conditions on the concentration-response relationship to NA and in some cases, to KCl. This was carried out on both the proximal and distal portions of the vessel, applying NA both intraluminally and extraluminally. Both portions showed similar characteristics and intraluminal administration of NA was more effective than the extraluminal administration. But this difference in potency was abolished when cocaine was included in the saline during the comparisons of the routes of administration of NA. Factors analysed (alone and in combination) included cocaine, propranolol, EDTA, extracellular and intracellular modification of pH, oxygen, [Ca2+]o (including the use of Ca2+ buffers). Following this the alpha-adrenoceptor population was analysed using selective antagonists (prazosin and rauwolscine) and Ca2+-entry was manipulated using nifedipine (blocker) and Bay K 8644 (facilitator). The calcium sensitivity of noradrenaline (NA) and potassium chloride (KCl)-induced contractions of vascular smooth muscle were investigated in calcium readdition experiments under different oxygen tensions and temperatures in the isolated perfused rat tail artery (male Wistar, 300-350g). We started by establishing the most favourable conditions for responses of the smooth muscle in the preparation, and making an extensive analysis of the influence of experimental conditions on the contraction-response relationship to NA and in some cases, to KCl. This was carried out on both the proximal and distal portions of the vessel, applying NA both intraluminally and extraluminally. Both portions showed similar characteristics and intraluminal administration of NA was more effective than the extraluminal administration. But this difference in potency was abolished when cocaine was included in the saline during the comparisons of the routes of administration of NA.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.795914  DOI: Not available
Share: