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.     

Spatial- versus object-oriented architectural environments: preference and perception

This study examined changes in perceptual response and preference a specific category of architectural environment by age groups. Understanding relationships among age, perception, and preference is important in creating more appropriate environments. The hypothesis was that individuals who score field-dependent on an Embedded Figures Test would prefer architectural environments which support spatial orientation, while individuals who are field-independent would prefer environments without information on spatial organization or an object-oriented space. It was also hypothesized that children and elderly persons would score more field-dependent and prefer spatially orienting spaces. 64 subjects ages 4 to 85 years were recruited from local schools, various organizations for seniors and adults, given the Embedded Figures Test to measure field dependence, and were compared. Their scores were compared by preference for one of the two environments. Hypotheses were not supported for the spaces overall, however, clear patterns regarding seating preference were identified. Children and seniors had significantly more field-dependent preferences.