title: Serotonergic activation of locomotor behavior and posture in one-day old rats.
abstract: The purpose of this study was to determine what dose of quipazine, a serotonergic agonist, facilitates air-stepping and induces postural control and patterns of locomotion in newborn rats. Subjects in both experiments were 1-day-old rat pups. In Experiment 1, pups were restrained and tested for air-stepping in a 35-min test session. Immediately following a 5-min baseline, pups were treated with quipazine (1.0, 3.0, or 10.0 mg/kg) or saline (vehicle control), administered intraperitoneally in a 50 μL injection. Bilateral alternating stepping occurred most frequently following treatment with 10.0 mg/kg quipazine, however the percentage of alternating steps, interlimb phase, and step period were very similar between the 3.0 and 10.0 mg/kg doses. For interlimb phase, the forelimbs and hindlimbs maintained a near perfect anti-phase pattern of coordination, with step period averaging about 1s. In Experiment 2, pups were treated with 3.0 or 10.0 mg/kg quipazine or saline, and then were placed on a surface (open field, unrestrained). Both doses of quipazine resulted in developmentally advanced postural control and locomotor patterns, including head elevation, postural stances, pivoting, crawling, and a few instances of quadrupedal walking. The 3.0 mg/kg dose of quipazine was the most effective at evoking sustained locomotion. Between the 2 experiments, behavior exhibited by the rat pup varied based on testing environment, emphasizing the role that environment and sensory cues exert over motor behavior. Overall, quipazine administered at a dose of 3.0 mg/kg was highly effective at promoting alternating limb coordination and inducing locomotor activity in both testing environments.
authors.affiliation: Idaho State University, Department of Psychology, Pocatello, ID, United States.
authors.forename: Hillary E
authors.initials: HE
authors.lastname: Swann
authors.affiliation: Idaho State University, Department of Psychology, Pocatello, ID, United States.
authors.forename: R Blaine
authors.initials: RB
authors.lastname: Kempe
authors.affiliation: Idaho State University, Department of Psychology, Pocatello, ID, United States.
authors.forename: Ashley M
authors.initials: AM
authors.lastname: Van Orden
authors.affiliation: Idaho State University, Department of Psychology, Pocatello, ID, United States. Electronic address: brummich@isu.edu.
authors.forename: Michele R
authors.initials: MR
authors.lastname: Brumley
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D004305:Dose-Response Relationship, Drug; D005121:Extremities / Q000502:physiology; D005260:Female; D008124:Locomotion / Q000187:drug effects / Q000502:physiology*; D008297:Male; D011187:Posture / Q000502:physiology*; D011597:Psychomotor Performance / Q000187:drug effects / Q000502:physiology*; D011814:Quipazine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism*; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D013997:Time Factors
chemical_list: D017366:Serotonin Receptor Agonists; D012701:Serotonin; D011814:Quipazine
keywords: Interlimb coordination; Locomotion; Neonatal rat; Posture; Quipazine; Stepping