Author/Editor		Pretnar, Janja
Title		Vpliv stimulacije simpatičnega živčnega sistema na možganski krvni obtok v različnih starostnih obdobjih
Type		monografija
Place		Ljubljana
Publisher		Medicinska fakulteta
Publication year		1999
Volume		str. 44
Language		slo
Abstract		Cold pressor test evokes generalized activation of the sympathetic nervous system. It is well known that sympathetic innervation mediates vasoconstriction of the cerebral blood arteries at the base of the skull. Transcranial Doppler sonography detects changes in the cerebrovascular circulation by monitoring blood-flow velocity. Two authors have already measured changes of blood flow velocity during cold pressor test, but the results were contradictory. In other studies authors used different methods of sympathetic nervous system stimulation, which were not specific. In our study we wanted to find out how a specific sympathetic nervous system stimulation by cold pressor test influences-blood flow velocity by means of an improved TCD method, in order to explain that influence, and to show that the method enables the detection of intracranial sympathetic nervous system function. The function of the sympathetic nervous system is diminished with age. Therefore we expected the effect of the cold pressor test on blood-flow velocity would also be smaller with age. Sixty-six healthy volunteers (mean age 39.9 +- 12.,2 years) participated in our study. They were divided into four subgroups according to their age; < 30 years, 30-40 years, 40-50 years and > 50 years. Blood-flow velocity was measured in both middle cerebral arteries by means of two 2MHz probes. Simultaneously, mean arterial blood pressure and heart rate were measured by final press and ECG. End-tidal CO2 was measured with an infrared capnograph. The experiment consisted of a 5-minute baseline period followed by 3-minute immersion of the right hand into ice water. To determine v,r, over a chosen time interval the TCD-8 software was utilized. Student t-test was used to compare variables before and during cold pressor test. Analysis of variance was used for comparison of variables in the four subgroups. (Abstract truncated at 2000 characters)
Descriptors		SYMPATHETIC NERVOUS SYSTEM CEREBROVASCULAR CIRCULATION BRAIN BLOOD FLOW VELOCITY CEREBRAL ARTERIES ADULT BLOOD PRESSURE HEART RATE COLD ULTRASONOGRAPHY, DOPPLER, TRANSCRANIAL ELECTROCARDIOGRAPHY CAPNOGRAPHY AGE FACTORS