Influence of emotional and physical stimuli on pressure in the isolated vein segment.

Generalized alterations in venous tone may shift large amounts of blood within the vascular system. Both physical and emotional stimuli are capable of affecting venous tone. The present report is a study in healthy males of the effects of certain of these factors on pressure (tone) in a peripheral vein segment isolated by means of specially designed, Plexiglas vein oecluders. The emotional stimuli employed were the most effective of the group in inci'easing venous tone. V EXOUS tone in isolated peripheral vein segments increases in association with a variety of physical stimuli including the Valsalva and Miiller maneuvers, foot-down tilting, exercise, hyperventilation, cold and 5 per cent carbon dioxide inhalation. 1 '-It is reported also that "apprehension" 1 " 3 and certain "mental states" including 'thought," "interest, anger, 'fear, and "dozing" affect venous tone. 3 "Dozing" is associated with a decrease, "fear" with an increase or decrease, and all others with an increase in tone. The present study was designed to determine the effects of certain emotional stimuli on the peripheral venous tone of individuals with normal cardiovascular systems and to compare these effects with specific physical activities. The basic hypothesis states that increases in peripheral venous segment pressure (PYSP) in response to emotional stimuli will be related in height and duration to the intensity of the stimulus as interpreted by the subject and will be as great or greater than increases in response to physical activities of types which may directly or indirectly increase venous pressure. 580 METHODS Six paid subjects, ages 20 to 25, were selected from a group of healthy university student volunteers on the basis of their having prominent, accessible right forearm vein segments without demonstrable tributaries. Studies were conducted in an air-conditioned room with the subjects supine on a hospital bed. PVSP was measured by means of a calibrated indwelling polyethylene catheter (Clay-Adams PE 50) filled with heparin (10 mg./ml.), introduced through a no. 17 needle under local anesthesia into the distal portion of the vein segment. The needle was removed from the vein over the catheter and the latter connected to a three-way stopcock on a Statham P-23 BB 0 to 5 cm. Hg strain gage. The second arm of the stopcock held a 5 ml. syringe with a dilute solution of heparin in isotonic saline (2 mg./ml.) used occasionally to flush the system. Heparin has been reported not to affect venous reactivity. 2 …