title: Improvements in self-administration studies based on changes in skin button type and surgical technique.
abstract: BACKGROUND
  These studies, ranging in duration from 3 to 8months, evaluated the patency and longevity of the intravenous (IV) self-administration surgical model in male Sprague Dawley rats. Surgeries were categorized and assessed based on the number of catheter and/or skin button repairs required per animal across four separate self-administration studies. Design improvements in skin button types and changes in surgical procedures were chronologically tracked and assessed.
  
  
  METHODS
  Animals were evaluated under a self-administration paradigm in which they were trained to respond for a food reward under a fixed ratio schedule (FR5 or FR10). Animals were then surgically prepared with a femoral catheter and skin button port. Following recovery, animals were returned to food-maintained responding for at least 5 sessions and subsequently trained to respond for injections of a reinforcing drug. Once drug training criteria was established, the effects of vehicle or varying doses of test articles were evaluated. Animals were tested in operant chambers one hour each day 5days a week and the length of each study was recorded. Differences in the number of repairs per study as well as the total number of repairs were tabulated.
  
  
  RESULTS
  Study length was directly correlated to the mean number of repairs occurring per study, with study length increasing as the total number of repairs increased. The majority of repairs were skin button-related issues. Multiple combinations of skin button types and surgical techniques were implemented across time to evaluate model efficiency and decrease overall cycle time per study. Initial combinations produced a greater number of repairs on a per study basis. However, the skin button type and surgical technique combination that resulted in the fewest number of total repairs used a lateral incision with a dorsal biopsy punch.
  
  
  CONCLUSIONS
  The combination of improvements in skin button type and surgical techniques drastically decreased the number of surgical repairs required per study, increasing efficiency and thereby decreasing the overall cycle time for study completion.
authors.affiliation: Covance Laboratories, 671S. Meridian Rd., Greenfield, IN, USA.
authors.forename: Lindsey M
authors.initials: LM
authors.lastname: Gilbert
authors.affiliation: Covance Laboratories, 671S. Meridian Rd., Greenfield, IN, USA.
authors.forename: Mario P
authors.initials: MP
authors.lastname: Sgro
authors.affiliation: Covance Laboratories, 671S. Meridian Rd., Greenfield, IN, USA.
authors.forename: Deah L
authors.initials: DL
authors.lastname: Modlin
authors.affiliation: Covance Laboratories, 671S. Meridian Rd., Greenfield, IN, USA.
authors.forename: Nathaniel J
authors.initials: NJ
authors.lastname: Wheat
authors.affiliation: Covance Laboratories, 671S. Meridian Rd., Greenfield, IN, USA.
authors.forename: Mary J
authors.initials: MJ
authors.lastname: Kallman
mesh_terms: D000818:Animals; D002404:Catheterization / Q000379:methods; D003042:Cocaine / Q000008:administration & dosage; D003216:Conditioning, Operant; D005502:Food; D008297:Male; D008874:Midazolam / Q000008:administration & dosage; D051381:Rats; D017207:Rats, Sprague-Dawley; D012055:Reinforcement Schedule; D012646:Self Administration; D012867:Skin
chemical_list: D003042:Cocaine; D008874:Midazolam
keywords: Catheter; Longevity; Methods; Patency; Rat; Self-administration; Skin button; Surgical technique