UPTAKE OF CATECHOLAMINES BY THE HEARTS OF RABBITS TREATED WITH SEGONTIN,
Abstract
A single i.v. injection of 8 mg/kg of Segontin caused a fall in the NA content of rabbit hearts to less than 10 per cent of their normal value in about 2 hrs. After 4 hrs the tissue content of NA started to rise again and after 24 hrs it had recovered to about one third of its normal value. An i.m. injection of 0.75 mg/kg NA 2 hrs after Segontin treatment, caused a temporary rise in the NA content of the heart to the normal value. NA was increased in the coarse particle fraction, the high speed sediment and in the particle free supernatant fraction of the heart after homogenization, indicating that the exogenous NA is temporarily filling the available storage sites. An i.v. infusion of NA (10 micrograms/kg/min for 20 min) caused an uptake of NA into the heart previously depleted by Segontin, followed by a rapid and then slower release of the NA. The uptake of 1-NA and d-NA and also of 1-A and d-A showed stereochemical specificity in favour of the 1-isomers. Phenoxybenzamine blocked the uptake of NA into the heart of rabbits depleted by Segontin, whereas DCI had only a small blocking effect. Phenoxygenzamine by itself reduced the NA content of all fractions of the heart. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 20, 1964
- Accession Number
- AD0623374
Entities
People
- B. R. Mackenna