Chapter 9 Basic Experiments of Neurobiology Experiment 1 Brain Stereotaxic Technique Functional Experimental Science

Content Experimental objectives 1 Experimental procedures 2 Precautions 3 Results 4 Discussion 5

Experimental Objectives By performing the experiment, you are expected to be familiar with primary structure, principle and operating method of stereotaxic apparatus, to be familiar with the method for locating the nucleus in brain and intracerebroventricular micro- injection with stereotaxic apparatus, to have a through grasp of usage of animal brain atlas.

Experimental Procedures General anesthesia and fixation 1 An adult rat weighing 200~230g is anesthetized with 4% chloral hydrate (400 mg/kg, i.p.). the ear bars should be gently inserted into the external auditory meatus, and the head is kept in the middle. The upper incisor is inserted into the hole of incisor plate,

Experimental Procedures Craniotomy and positioning 2 After hair clearance and regular disinfection, a 1 cm long incision is cut along sagittal suture. The skull surface is wiped with hydrogen peroxide to expose the bregma and lambda, as well as the coronal and sagittal sutures. According to the coordinates of lateral ventricle (Fig 9-4), a small hole is punched on the skull with a dental drill..

Experimental Procedures Microinjection to the lateral ventricle 3 The rat is slowly injected via the lateral ventricle (LV) with 10~20 μl blue ink by a microsyringe. The syringe should be removed 3-5 min later in order to prevent the retrograde flow of ink.

Experimental Procedures Observations 4 The brain should be taken out from the cranium and be cut coronally with a razor blade to verify whether blue ink is in the lateral ventricle.

Precautions The structure of stereotaxic apparatus is very delicate and easily injured, so the manipulation should be very gentle and avoid any forced movement.. 1 When the sliding rules are adjusted three-dimensionally, it should be verified whether the sliding rules of three plans are perpendicular to each other. 2 The ear plugs should be inserted exactly into the external auditory meatus, and symmetrically from both sides in order to keep the rat head at the middle position in the stereotaxic apparatus. Be sure to prevent the external auditory meatus from being misplugged, soft tissue from embedding and readings on two sides from being asymmetry.. 3

Results It could be find that blue ink is in the third ventricle. 1 2 Blue ink is in the lateral ventricle.