Inhibition of the LH Surge by Restraint Stress in Cyclic Rats: Studies on the Role of GABAA and GABAB Receptors

There is evidence that stress can alter the activity in the brain of gamma-aminobutyricacid (GABA), a neurotransmitter that has been implicated in the regulation of LH secretion. In the present study the role of GABA in the restraint stress-induced inhibition of the LH surge was investigated in the intact cyclic rat. Intracerebroventricular (icv) administration of the GABAA receptor agonist muscimol (0.1, 0.5 or 1 μg) 5 min before the presumed onset of the pro-oestrous LH surge (at 0900 h) caused a dose dependent suppression of the surge. A single dose of the GABAB receptor agonist baclofen (1 μg; icv) injected at 0855 h postponed the onset of the LH surge, and repeated injections at 0855 and 1130 h suppressed the surge. These data indicate that GABA-ergic activity in the brain can inhibit the LH surge in the cyclic rat via GABAA and GABAB receptors. Pro-oestrous rats were subjected to 5 hrs of restraint starting at 0855 h. Pretreatment with the GABAA receptor antagonist bicuculine (1 μg; icv) at 0840, 0940 and 1040 h or pretreatment with the GABAB receptor antagonist phaclofen (10 μg; icv) at 0840 h were ineffective in preventing the restraint-induced inhibition of the LH surge. The results suggest that GABAA and GABAB receptors are not involved in the inhibitory effect of restraint stress on the LH surge.     

An examination of the Clinical Impairment Assessment among women at high risk for eating disorder onset

Identifying measures that reliably and validly assess clinical impairment has important implications for eating disorder (ED) diagnosis and treatment. The current study examined the psychometric properties of the Clinical Impairment Assessment (CIA) in women at high risk for ED onset. Participants were 543 women (20.6 ± 2.0 years) who were classified into one of three ED categories: clinical ED, high risk for ED onset, and low risk control. Among high risk women, the CIA demonstrated high internal consistency (α = 0.93) and good convergent validity with disordered eating attitudes (rs = 0.27-0.68, ps < 0.001). Examination of the CIA's discriminant validity revealed that CIA global scores were highest among women with a clinical ED (17.7 ± 10.7) followed by high risk women (10.6 ± 8.5) and low risk controls (3.0 ± 3.3), respectively (p < 0.001). High risk women reporting behavioral indices of ED psychopathology (objective and/or subjective binge episodes, purging behaviors, driven exercise, and ED treatment history) had higher CIA global scores than those without such indices (ps < 0.05), suggesting good criterion validity. These data establish the first norms for the CIA in a United States sample. The CIA is psychometrically sound among high risk women, and heightened levels of impairment among these individuals as compared to low risk women verify the relevance of early intervention efforts.