Publication Date


Document Type


Committee Members

Michael Hennessy (Advisor), John Pearson (Committee Member), Patricia Schiml-webb (Committee Member)

Degree Name

Master of Science (MS)


Maternal separation in guinea pigs produces a biphasic response consisting of an active behavior phase followed by a phase of passive behavior (crouched stance, piloerection, and eye closure). Previous studies suggest that pro-inflammatory cytokines mediate passive behavior during the passive phase. It is also known that guinea pig pups separated on two consecutive days show a significant increase (sensitization) in full passive behavior on the second day. The current study examined the persistence and role of pro-inflammatory activity in the sensitization of passive behavior in maternally separated guinea pigs. Guinea pig pups were assigned to one of four groups differing in their treatment on Day 1. The groups were either: (1) injected with saline and not separated; (2) injected with saline and separated; (3) injected with lipopolysaccharide (LPS) to induce cytokine activation and not separated; or, (4) injected with LPS and separated. All pups were separated on Day 2 and again on Day 5. By Day 5, sensitization of passive behavior was observed for all groups. LPS on Day 1 did not increase passive behavior on Day 2, but appeared to enhance the effect of separation on Day 5. These data indicate that sensitization of the passive behavior of maternally separated pups persists beyond a single day. Further the results show that LPS induced activation of pro-inflammatory activity is not sufficient to account for the initial sensitization, but does appear to enhance later sensitization effects.

Page Count


Department or Program

Department of Neuroscience, Cell Biology & Physiology

Year Degree Awarded


Included in

Anatomy Commons