Venizeleio Hospital Crete

The effect of various parameters on the mediation of the fear-inhibited light reflex was examined. The light reflexes of 16 healthy men were measured across four light probe intensities, either in the presence of white noise alone or when the white noise was associated with the threat of either an electric shock or an acoustic sound blast. The white noise alone did not affect the light reflex amplitude. Both types of threat were subjectively anxiogenic and inhibited the light reflex across all light probe intensities, the threat of shock being more potent than the threat of sound blast. Importantly, the effect of either type of threat on the light reflex amplitude was found to increase with increasing light probe intensity, suggesting that brighter light probes may become more relevant motivationally in the threat condition, thus attracting greater allocation of attentional/cognitive resources.

Fear (e.g. associated with the threat of an electric shock) causes an increase in initial pupil diameter (IPD) and a decrease in the amplitude of the light reflex response. There is evidence for dissociation between the two responses to threat: only the reduction in light reflex response amplitude is sensitive to the anxiolytic drug diazepam. We examined the effects of peripheral sympathetic blockade with the α1-adrenoceptor antagonist dapiprazole on both responses to threat on the basis of the hypothesis that only the response of the IPD will be affected, whereas the response of the light reflex will remain unaffected. Twelve healthy volunteers (Experiment 1) and eight healthy volunteers with smaller pupils (Experiment 2) participated in one experimental session. Dapiprazole 0.5% (two drops of 20 µl, three times) was instilled in the subjects’ right or left eye while the contralateral eye was treated with placebo eye drops (artificial tear, two drops of 20 µl, three times) accordin...

Rationale The human pupil may be a suitable physiological test system for the assessment of excessive daytime sleepiness (EDS), but pupillometric assessment could be confounded by medication for comorbid hypertension and mood disorders. Objectives We examined the profile of the 5HT-2/α1/H1 antagonist ketanserin, the 5HT1a agonist buspirone and the beta adrenoceptor antagonist propranolol on pupillary and other measures of arousal. Materials and methods Ketanserin (20 mg), buspirone (10 mg) and propranolol (40 mg) were administered in three independent experiments according to a crossover, placebo-controlled, double-blind design. Resting pupil diameter (RPD) was sampled over 5-min in darkness with infrared pupillometry. Tests also included critical flicker fusion frequency (CFFF), visual analogue scales (VAS), the pupillary light reflex and heart rate/blood pressure. Results Ketanserin reduced RPD, CFFF, VAS-rated arousal and blood pressure and increased the light reflex amplitude. Buspirone reduced RPD and blood pressure. Propranolol reduced heart rate but had no effects on pupillary functions or any arousal measure. Conclusions Ketanserin but not propranolol had a fully sedative profile and may confound pupillometric assessment of EDS. Beta adrenergic receptors do not appear to participate in arousal and pupillary functions, while 5HT1a receptors reduce pupil size without affecting arousal. Pupil size may not be used unequivocally as an index of the level of alertness in the case of drug-induced changes, when drugs interfere with the central pupil control mechanism in ways that are unrelated to their effects on arousal.

Serum levels of IL-1β, IL-6 and TNF-α were measured in 48 healthy, termed neonates on the 1st (N1), 5th (N5) and 40th (N40) day after birth, compared with those in maternal serum (MS), umbilical cord (UC) and adult controls. Cytokine values in N1 and N5 were significantly elevated, than those in UC and in controls(p<0.0001). IL-1β and IL-6 declined significantly from N1 to N40(p<0.0001), while TNF-α increased significantly from N1 to N5 and declined thereafter. MS∞IL-1β and IL-6, but not MS∞TNF-α, were significantly higher than those of controls(p<0.0001). IL-1β values depended on the mode of delivery. In conclusion, the increased concentrations of IL-1 β, IL-6 and TNF-α during the perinatal period might suggest their involvement in an inflammation like process during normal parturition, and reflect also a newborn immune response to the stress of delivery and environmental changes.