Effects of ethanol on the acoustic startle reflex in humans

Abstract

The effect of ethanol on human sensorimotor reactivity was assessed by examining the acoustic startle response. Twelve healthy normal subjects participated in a startle reflex experiment in which placebo or ethanol were given on separate days. Three types of startle probes were used. They consisted of pulse-alone bursts of white noise at 108 dB(A) and 99 dB(A) to explore startle reactivity, and of a 108 dB(A) pulse preceded by a 85 dB(A) prepulse stimulus (prepulse+pulse) to assess prepulse inhibition. Startle amplitude was larger to the 108 dB(A), compared to the 99 dB(A) pulse-alone probes. The prepulse stimulus significantly reduced the amplitude of the startle reflex elicited by the subsequent 108 dB(A) stimulus. The amplitude of the startle response was dramatically reduced by acute ethanol. The effects of ethanol on prepulse inhibition could not be assessed because the startle response was too small in the ethanol condition.

Effects of the beta-blocker propranolol on cued and contextual fear conditioning in humans

“…The lack of effect on sedation was also suggested by the startle data. Although the startle reflex in humans is very sensitive to sedative drugs (Grillon et al 1994b;, startle reactivity was not reduced by propranolol. Thus, it is unlikely that sedation affected the results of this study.…”

Anxiolytic effects of a novel group II metabotropic glutamate receptor agonist (LY354740) in the fear-potentiated startle paradigm in humans

“…Drugs known for their sedative effects, such as alcohol and the benzodiazepines, produce a dramatic reduction in baseline startle (Grillon et al 1994(Grillon et al , 2000Kumari et al 1996;Bitsios et al 1999;Rodriguez-Fornells et al 1999;Riba et al 2001). There is only one exception to this finding.…”

“…Of note, using very similar threat of shock paradigms, our group has been unable to obtain differences in fear-potentiated startle between patient groups (e.g. patients with panic disorder versus healthy controls; Grillon et al 1994) or drug treatment . In particular, we were unable to find in four separate experiments that benzodiazepine reduced fear-potentiated startle .…”

Effect of acute subcutaneous nicotine on prepulse inhibition of the acoustic startle reflex in healthy male non-smokers

“…There are relevant Þndings in the literature, which suggest that drowsiness alone would not increase PPI. For example, clonidine (Abduljawad et al 1996) and ethanol (Grillon et al 1994), both of which induce drowsiness and reduce the amplitude of startle response in healthy human subjects, do not a¤ect PPI. Further experiments to determine the e¤ects of acute oral administration of haloperidol (which may induce drowsiness) on the amplitude, habituation and PPI of the acoustic startle reßex in normal volunteers are under way in our laboratory.…”