Erythropoietin and Cytoprotective Cytokines in Experimental Traumatic Brain Injury - Tissue-Protective Cytokines: Methods and Protocols - page 147

Fig. 3 Position of rat in the stereotactic frame and connections for monitoring various physiological parameters
2. Controlled Cortical Impact: A pneumatic impactor is used for
rats and the voltage driven impactor for mice. The pneumatic
cylinder (with bore 1.875 and 5 cm stroke) is rigidly mounted
on a cross bar so that the position and the angle of impaction
can be adjusted over the rats head fixed in the frame. Impactor
tip (8 mm) is attached to the lower end of the cylinder. The
upper end is attached to the transducer core of the LVDT
(Linear variable differential transducer). The impact velocity
can be controlled by adjusting the pressure from the gas cylin-
der. The velocity and duration can be measured from the out-
put of LVDT and is displayed on the monitor (LabVIEW soft
ware). Pressures of 150, 35, and 15 psi applied to the impactor
usually result in impact velocities of approximately 5 m/s,
3 m/s, and 1 m/s, respectively. The depth of deformation is
adjusted by advancing the impactor tip. The parameters depend
on the type of study (mild vs. severe TBI) (Table 1 ). After
adjusting the parameters on the pneumatic impactor, a trial
impact is made to ensure the values as displayed on the monitor.
The animal is fixed on the frame (three point fixation—bilateral