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- Damber, Jan-Erik, et al.
(författare)
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Rhythmical oscillations in rat testicular microcirculation as recorded by laser Doppler flowmetry
- 1983
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Ingår i: Acta Physiologica Scandinavica. - : Wiley. - 0001-6772 .- 1365-201X. ; 118:2, s. 117-123
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Tidskriftsartikel (refereegranskat)abstract
- We have earlier reported that local testicular blood flow, recorded by laser Doppler flowmetry, shows large oscillations with a frequency of 5-10 min-1. In the present study it is proposed that the recorded oscillations represent mainly local microvascular blood flow variations rather than variations in total testicular blood flow or tissue movements. The reasons for this are: (a) Blood flow simultaneously measured at two separate sites showed oscillations with different frequencies. (b) A local subcapsular injection of room-tempered saline under one probe site eradicated oscillations under that probe but not under another adjacent probe. (c) When the testicular capsule was split open, recordings of blood flow continued to show oscillations. (d) The amplitude of the oscillations was rather large (peak to peak value about 50% of mean flow value). No movements of the testicular surface were seen. A 20 min continuous infusion of 0.4 microgram/min noradrenaline did induce a decrease in plasma testosterone concentration, but did not change the mean blood flow. However, the oscillations nearly completely disappeared during the infusion period. The present study also shows that laser Doppler flowmetry is a versatile method and the rat testis provides a suitable organ in the study of the origin and functional importance of these oscillations
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- Damber, Jan-Erik, et al.
(författare)
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Testicular blood flow measured with a laser Doppler flowmeter : acute effects of catecholamines.
- 1982
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Ingår i: Acta Physiologica Scandinavica. - : Wiley. - 0001-6772 .- 1365-201X. ; 115:2, s. 209-215
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Tidskriftsartikel (refereegranskat)abstract
- Laser Doppler flowmetry was used to continuously measure testicular blood flow in rats. The method was found applicable on surgically exposed testes. Regular oscillations in blood flow, with a periodicity of 8.6 +/- 0.7 cycles per minute (mean +/- SD), were observed in recordings from 22 to 23 rats. Clamping of the testicular artery reduced the blood flow signal to background values. Effects of catecholamines administered into the tail artery on testicular blood flow together with systemic effects on mean arterial blood pressure and heart rate were measured. It was found that noradrenaline as well as adrenaline caused a significant decrease in blood flow when 10 micrograms was injected. Only noradrenaline decreased the blood flow when 1 microgram was given. The large oscillations detected in the blood flow recordings disappeared quickly when 10 or 1 micrograms of both hormones was administered. It was concluded that catecholamines can exert rapid effects on testicular blood flow
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- Tenland, Torsten, 1952-
(författare)
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On laser Doppler flowmetry : methods and microvascular applications
- 1982
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A laser Doppler flowmeter for non-invasive microcirculatory blood flow studies has been developed. The tissue under study is illuminated by laser light (helium-neon laser, output power 2 mW) via an optical fibre and the Doppler shift oflight scattered in moving red cells is analysed. By the use of two photodetectors for detection of the backscattered light, the influences of mode interference and broadband noise from the laser and noise from surrounding light sources have been suppressed. The instrument is designed to give a continuous, stable and linear real-time measure of the flux of red cells (i.e. the number of red cells times their velocity) in the outermost layer (1 mm) of tissue, in which the red cell volume fractions are low or moderate. Linearity, measuring depth and the influence of blood oxygen tension were evaluated in a flow model with optical properties similar to those of human skin. Laser Dopplerflowmetry was found to be versatile for measurements of blood flow in human skin and rat testis and did not influence the flow under study.An extensive study of spatial and temporal variations of human skin blood flow was performed. As it was found that skin blood flow shows wide day-to-day variations and significant differences between adjacent probe sites, earlier reported "normal" values of skin blood flow were seriously questioned. It is proposed that this study can serve as a base for further functional studies.Testicular blood flow in rats was studied in order to evaluate acute effects of stress-linked substances such as adrenaline and noradrenaline. Both substances lowered the blood flow at high doses.Rhythmical variations of blood flow (frequency 5-12 min-1) in human skin and rat testis were observed and found to be in agreement with earlier findings in microscopic studies on other types of tissue. The nature and origin of this rhythmicity point towards a local regulatory mechanism operating also under "steady state" conditions.
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