Influence of cartilage on reactivity and on the effectiveness of verapamil in guinea pig isolated airway smooth muscle.

Details

• Personal Author:
  Farmer SG ; Fedan, Jeffery S. ; Hay DW ; Raeburn D
• Description:
  The effect of cartilage removal on the response of guinea-pig trachealis to bronchoconstrictors and the antispasmogenic and spasmolytic agent verapamil was studied. Basal calcium uptake by guinea-pig trachealis was known to be reduced by cartilage removal. Trachealis isolated from male English-short-hair-guinea-pigs showed decreased sensitivity to potassium-chloride and histamine in the absence of cartilage, consistent with the reported extracellular calcium dependency of these agents. In contrast, a change in sensitivity to methacholine was seen, consistent with the suggestion that this agent acts via intracellular calcium pools. High potassium-chloride concentrations showed a lesser effect of cartilage removal, suggesting that intracellular calcium might be utilized in its stimulation of smooth muscle contraction. Cartilage removal increased the antispasmogenic and spasmolytic effects of verapamil on contraction induced by histamine and methacholine. Verapamil was more effective at blocking existing contractions than preventing their development. This was consistent with the proposal that verapamil blocks the smaller influx of calcium occurring during the sustained secondary phase of contraction. A "use dependence" for verapamil was seen, which was similar to the effect seen in cardiac muscle. Possible mechanisms for this effect were discussed. The authors conclude that removal of cartilage reduces muscle reactivity and increases the potency of verapamil in guinea-pig trachealis, suggesting a role for cartilage derived calcium in excitation/contraction coupling mechanisms. [Description provided by NIOSH]
• Subjects:
  Laboratories Lung Musculoskeletal System Occupational Health Respiratory System Safety
• Keywords:
  NIOSH-Author; In-vitro-studies; Muscle-tissue; Pharmacology; Laboratory-animals; Pulmonary-system; Muscle-contraction; Drugs
• ISSN:
  0022-3565
• Document Type:
  Text
• Genre:
  Journal Article
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  450-454
• Volume:
  242
• Issue:
  2
• NIOSHTIC Number:
  nn:00180792
• Citation:
  J Pharmacol Exp Ther 1987 Aug; 242(2):450-454
• Federal Fiscal Year:
  1987
• NORA Priority Area:
  Pulmonary System Disorders
• Peer Reviewed:
  True
• Source Full Name:
  Journal of Pharmacology and Experimental Therapeutics
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:7dc847c09aedf140bc731323e8446b4703641ae07d6ad9e7b7238120dab30b8f7dcaa9b938d34d035f87873a0fe7fec262d5d13dcaf290925445e82b6de3b57d
• Download URL:
  https://stacks.cdc.gov/view/cdc/247639/cdc_247639_DS1.pdf
• File Type:
  [PDF - 168.02 KB ]