A Practical Approach, Second Edition=Ronald D. Ho.pdf

478 DEVELOPMENTAL REPRODUCTIVE TOXICOLOGY: A PRACTICAL APPROACH, SECOND EDITIONwrithing, circling, biting, and gait and coordination abnormalities. The observations and/or scoresare recorded on the appropriate form.2. Removing from Cage ObservationsWhile the adult rat is being removed from its cage, it is observed for the following characteristics:ease of removal, ease of handling, vocalizations, muscle tone (e.g., limp, rigid), bite marks on tailand or paws, palpebral closure, piloerection, fur appearance (includes observation of skin, mucousmembranes, and eyes), lacrimation, salivation, and exophthalmos. The observations and/or scoresare recorded on the appropriate form.3. Standard Open Field Arena ObservationsThe adult rat is placed in the standard open field arena for approximately 2 min. The techniciansobserves and assesses the following characteristics: presence of righting reflex, posture, respirationease, rate of respiration, convulsions, tremors, muscle fasiculations, muscle spasm, grooming, gaitand coordination abnormalities (e.g., unbalanced, ataxic, unable to move), level of arousal (e.g.,stupor, excited), palpebral closure, diarrhea, polyuria, rearing (number of times both forepaws arelifted above cageboard), and vocalizations. The observations and/or scores are recorded on theappropriate form.4. Manipulations in the Standard Open Field ArenaWhile the adult rat is in the open field arena, the technician observes and assesses the followingcharacteristics: approach and touch response, auditory stimulus, and tail pinch. For the approachand touch response, the rat is rapidly approached toward the front of its head with a blunt probe(e.g., a finger) and then is touched between the eyes. The observer records the presence or absenceof the approach and touch response. For auditory stimulus, an appropriate stimulus (e.g., fingercricket or snap) is presented directly above the rat’s head and observer records the presence orabsence of the flinch reflex or other responses. For the tail pinch, the observer grasps the middleportion of the tail firmly between the thumb and index finger and pinches the tail. The observerrecords the presence or absence of a tail pinch response. Additional observations are noted whenpresent (e.g., sniffing, head weaving, Straub tail, syncope [loss of consciousness], stereotypicbehavior).5. Grip Strength ManipulationsThe technician selects the appropriate setting for the force gauge (for example, a Chatillon DigitalForce gauge) and tares it. The adult rat is grasped to provide support for the weight of the animal.The paws are brought into contact with the appropriate grip surface, ensuring that only forelimbpaws come into contact with the forelimb grip surface and only the hind limb paws come intocontact with the hind limb grip surface. The rat is allowed to grasp the surface with both pawsbeing tested. The technician then pulls the animal with a fluid motion away from the gauge untilthe paws release. The technician performs at least three forelimb and three hind limb trials for eachanimal. The gauge should be tared between trials, and the gauge readouts are documented on theappropriate form.6. Foot SplayThe technician applies ink to both heels of the hind paws of the adult rat. The rat is grasped bythe base of the tail with one hand and around the thorax with the other hand and held approximately© 2006 by Taylor & Francis Group, LLC