Rat pinealectomy: a modified direct visual approach

Carla Cristina Maganhin,Manuel De Jesus Simões,Luiz Fernando Portugal Fuchs,Edmund Chada Baracat,José Maria Soares Júnior,Joaquim Evêncio Neto,Ricardo Santos Simões,Ricardo Martins Oliveira-Filho

doi:10.1590/s0102-86502009000400013

Abstract

To report a new, direct visual approach for rat pinealectomy. Eighty adult female rats (Rattus norvegicus albinus EPM-1 strain) were weighted and anesthetized intraperitoneally with 15 mg/kg xylazine and 30 mg/kg ketamine. The animal was fastened to a dissection table, an incision was made in the skin and the subcutaneous tissue, bringing the lambda into view. The skullcap was opened with a dental drill, bringing the cerebral hemispheres and the superior sagittal sinus into view. The pineal gland, located under the venous sinus, was removed in a single piece using tweezers. Next, the bone fragment was returned to its place and the surgical layers were sutured. This new technique is easy to be done, avoids bleedings and removes only the pineal gland without damage to the remaining encephalon. In addition it makes possible the achievement of a sham surgery, allowing the pineal gland to remain intact. The proposed technique intends to facilitate studies aiming to better understanding the complexity and importance of the pineal gland on reproductive and other body systems.

Highlights

Many aspects of pineal metabolism make this gland an excellent subject for the study of biological rhythmicity
The dark–light conditions are transmitted through the eyes to the suprachiasmatic nucleus, which signals are inhibited by light and are activated in the dark as a consequence of the absence of such inhibition[3]
In order to solve this problem in removing the gland and maintaining a good clinical condition of the animal after surgery, we modified the technique of pinealectomy

Summary

Introduction

Many aspects of pineal metabolism make this gland an excellent subject for the study of biological rhythmicity. The pattern of melatonin secretion by the pineal gland mediates the effects of day length on the seasonal reproductive cycle[3]. The necessity of studying the physiology and the metabolism of the pineal gland and the biologic rhythm of many species, explains the importance of its removal (pinealectomy).

Results

Conclusion