Electrophysiological Assessment (The Multiple Sleep Latency Test) of the Biphasic Effects of Ethanol in Humans

Abstract

The Multiple Sleep Latency Test (MSLT) was used to assess the effects of ethanol at the peak and descending phases of the breath ethanol curve. Ethanol (0.75 g/kg) was administered (at 0900 hr) to 8 healthy, normal-sleeping men, aged 21 to 45 years old after 8 hr of sleep the previous night. MSLTs were conducted and breath ethanol concentrations (BrECs) were measured at 15, 45, 75, 105, 225, and 345 min after drinking was completed. Subjective measures were administered immediately before each sleep latency test. BrECs over the first 75 min (tests 1 to 3) peaked and differed from all subsequent tests (tests 4 to 6) over which BrECs declined. Sleep latency and subjective measures were averaged over tests 1 to 3 and 4 to 6. There was a significant increase in mean sleep latency relative to placebo for tests 1 to 3 and a significant reduction for tests 4 to 6. The subjective measure of stimulation sedation, the Biphasic Alcohol Effects Scale, showed lessened sedation after ethanol versus placebo on tests 1 to 3, compared with tests 4 to 6. This study confirmed the presence of a biphasic ethanol effect using an electrophysiological method (MSLT), showing increased physiological alertness on the peak phase of the BrEC curve and increased sedation on the descending phase. Relative to the effects observed on the MSLT with other low-dose stimulant drugs, the stimulatory effect of ethanol was mild.

Ethanol Influences on Native T-Type Calcium Current in Thalamic Sleep Circuitry

“…Increased T current availability with low ethanol concentration exposure could lead to increased spindle wave activity and duration of Stage II sleep. This is precisely what has been reported in the clinical literature with moderate doses of ethanol (0.55 g/kg of body weight) administered to nonalcoholic test subjects resulting in a decrease in rapid eye movement (REM) sleep and an enhancement of slow wave sleep time and spindle wave activity (Stone, 1980;Papineau et al, 1988;Landolt et al, 1996).…”

Alcohol continues to affect sleepiness related driving impairment, when breath alcohol levels have fallen to near‐zero

“…The present findings of the 'rebound' subsequent improvement in driving performance in sleepy drivers having consumed alcohol, was unexpected. Alcohol can have a biphasic effect, but typically its stimulatory effects are seen prior to reaching peak BrACs and at higher initial doses (Papineau et al, 1998). Nevertheless sleepiness with moderate alcohol consumption remains a dangerous combination even when the additional alcohol effect subjectively seems to have worn off.…”

Memory encoding and retrieval on the ascending and descending limbs of the blood alcohol concentration curve

“…Memory, abstract reasoning, attention, and reaction/anticipation time have been found to be impaired on the ascending limb (Hurst and Bagley 1972;Jones and Vega 1972;Jones 1973;Nicholson et al 1992), a limb usually associated with an increase in skin conductance (Pishkin et al 1983), arousal and positive mood, but also with aggression. The descending limb usually produces sedation, negative mood (Babor et al 1983;Sutker et al 1983;Lukas et al 1986;Giancola and Zeichner 1997;Papineau et al 1998;Erblich and Earleywine 2003), and impaired executive function (Pihl et al 2003). However, the biphasic effects of alcohol on mood, psychomotor/cognitive performance, and heart rate can vary between individuals depending on their family history and drinking habits (Conrod et al 1997;Hiltunen 1997;Holdstock and de Wit 1998;King et al 2002).…”