Changes in sensorimotor inhibition across the menstrual cycle: Implications for neuropsychiatric disorders

Acoustic prepulse inhibition (PPI) is considered an important biomarker in animal studies of psychosis and a number of psychiatric conditions. Nicotine has been shown to improve acoustic PPI in some animal strains and in humans. However, there is little data on effects of nicotine on acoustic PPI in schizophrenia patients using a double-blind, placebo-controlled study design. The primary aim of the current study was to test the effect of nicotine nasal spray on acoustic PPI in schizophrenia patients. The secondary aim was to test nicotine effect on prepulse facilitation (PPF). The study included 18 schizophrenia patient smokers and 12 healthy control smokers, tested in a double-blind, placebo-controlled, crossover, randomized design immediately after nicotine or saline placebo nasal sprays. PPI was tested using 120 ms prepulse-pulse interval. PPF was tested using 4500 ms prepulse-pulse interval. The results showed a significant main effect of drug on PPI in that nicotine improved PPI compared to placebo (p ¼ 0.008) with no drug by diagnosis interaction (p ¼ 0.90). Improvement in PPI in response to nicotine was significantly correlated with the baseline severity of clinical symptoms (r ¼ 0.59, p ¼ 0.02) in patients. There was no significant drug or drug by diagnosis interaction for the 4500 ms prepulse-pulse interval condition. However, nicotine improved inhibition in a subgroup of subjects exhibiting PPF (p ¼ 0.002). In conclusion, the findings confirmed that nicotine transiently improves acoustic PPI in schizophrenia patients. Additionally, schizophrenia patients with more clinical symptoms may have benefited more from nicotinic effect on PPI.

Section: Discussionmentioning

confidence: 60%

Nicotine Effect on Prepulse Inhibition and Prepulse Facilitation in Schizophrenia Patients

Hong

Wonodi

Lewis

et al. 2007

“…Several studies have demonstrated reduced PPI during phases of the menstrual/estrous cycle during which either estrogen or estrogen and progesterone levels are elevated (ie, late follicular and mid-luteal in women, proestrus in rats) (Jovanovic et al, 2004;Koch, 1998;Swerdlow et al, 1997). Other studies, however, have demonstrated enhanced PPI following estradiol administration (Van den Buuse and Eikelis, 2001).…”

Section: Discussionmentioning

confidence: 99%

“…Currently no studies have examined PPI in women with postpartum psychosis. However, studies have shown that variations in circulating hormones can modulate PPI (Swerdlow et al, 1997;Koch, 1998) suggesting an interaction between the neural systems that regulate sensorimotor gating and endocrine status.…”

Section: Introductionmentioning

confidence: 99%

Sensorimotor Gating and Dopamine Function in Postpartum Rats

Byrnes

Bridges

Scanlan

et al. 2006

There is much speculation regarding the effects of estrogen withdrawal at the end of pregnancy on forebrain dopamine, however, few studies have directly examine changes in this system postpartum. The present work sought to determine what changes in forebrain dopamine function occur in the postpartum rat. Specifically, prepulse inhibition of the acoustic startle response (PPI) was measured in primiparous female rats on postpartum day 2 (PPD2) or 14 (PPD14) following treatment with saline or the dopamine D2 agonist, quinpirole. Diestrus (DI) females served as controls. Dopamine content and turnover as well as cyclic AMP (cAMP) accumulation were determined within the nucleus accumbens and dorsal striatum in these same females. In addition, circulating levels of plasma corticosterone, estradiol and progesterone were measured. PPI was significantly disrupted in both postpartum groups. This effect was associated with decreased cAMP content within the nucleus accumbens. Quinpirole treatment (0.1 and 0.5 mg/kg) dose-dependently disrupted PPI in DI controls while PPD2 and PPD14 animals demonstrated reduced sensitivity to the D2 agonist. PPD14 animals demonstrated increased startle amplitude, an effect that was attenuated by quinpirole treatment. PPD14 females were also less sensitive to quinpirole-mediated reductions in DA turnover within the nucleus accumbens and both PPD2 and PPD14 females had an attenuated response to the stimulatory effects of quinpirole on corticosterone secretion. Collectively these findings suggest that the postpartum period is associated with reduced sensorimotor gating and altered forebrain DA systems, which may be related to shifts in circulating hormones.

“…All subjects received placebo and three graded doses of psilocybin: 115, 215, and 315 mg/ kg body weight in a randomized and counterbalanced order separated by 4 week intervals. As a result of variations of PPI with menstrual cycle, women were tested in the first 5 days of their follicular phase where PPI has been shown to be most robust (Swerdlow et al, 1996). The doses of psilocybin were selected to be sufficient to assure differential psychological effects across doses (Hasler et al, 2004).…”

Section: Methodsmentioning

confidence: 99%

The Effects of the Preferential 5-HT2A Agonist Psilocybin on Prepulse Inhibition of Startle in Healthy Human Volunteers Depend on Interstimulus Interval

Vollenweider

Csomor

Knappe

et al. 2007

153

Schizophrenia patients exhibit impairments in prepulse inhibition (PPI) of the startle response. Hallucinogenic 5-HT 2A receptor agonists are used for animal models of schizophrenia because they mimic some symptoms of schizophrenia in humans and induce PPI deficits in animals. Nevertheless, one report indicates that the 5-HT 2A receptor agonist psilocybin increases PPI in healthy humans. Hence, we investigated these inconsistent results by assessing the dose-dependent effects of psilocybin on PPI in healthy humans. Sixteen subjects each received placebo or 115, 215, and 315 mg/kg of psilocybin at 4-week intervals in a randomized and counterbalanced order. PPI at 30-, 60-, 120-, 240-, and 2000-ms interstimulus intervals (ISIs) was measured 90 and 165 min after drug intake, coinciding with the peak and post-peak effects of psilocybin. The effects of psilocybin on psychopathological core dimensions and sustained attention were assessed by the Altered States of Consciousness Rating Scale (5D-ASC) and the Frankfurt Attention Inventory (FAIR). Psilocybin dosedependently reduced PPI at short (30 ms), had no effect at medium (60 ms), and increased PPI at long (120-2000 ms) ISIs, without affecting startle reactivity or habituation. Psilocybin dose-dependently impaired sustained attention and increased all 5D-ASC scores with exception of Auditory Alterations. Moreover, psilocybin-induced impairments in sustained attention performance were positively correlated with reduced PPI at the 30 ms ISI and not with the concomitant increases in PPI observed at long ISIs. These results confirm the psilocybin-induced increase in PPI at long ISIs and reveal that psilocybin also produces a decrease in PPI at short ISIs that is correlated with impaired attention and consistent with deficient PPI in schizophrenia.