Morphological and quantitative features of mitral cells in the rat olfactory bulb after administration of propranolol

To determine the cytoplasmic morphological changes in the mitral cells and quantitative changes (number of mitral cells and thickness of mitral cell layer in microns) in the rat olfactory bulb after administration of propranolol.

Experimental study.

The Department of Anatomy, University of Health Sciences, Lahore, from January 2006 to January 2007.

Twenty samples were obtained from two randomly divided groups of rats, each comprising 10 animals for control and experimental work respectively. Each group was treated with normal saline (5 ml/kg) and propranolol (1 mg/kg) respectively for one month. The skull was fixed in 20% formalin for 10 days and decalcified in 10% formalin/10% nitric acid. The olfactory bulb along with olfactory cortex was dissected. After processing, 10 microns thick sections were obtained. The slides were stained with Hematoxylin and Eosin and Bielschowksy's silver stain (Glees-Marsland modification) and studied under light microscope. The morphology, quantitative analysis of mitral cell layer and the number of mitral cells were studied in the histological study and compared using t-test with significance at p < 0.05.

In the propranolol treated group changes observed in the morphology of the mitral cells included presence of cytoplasmic vacuoles at the periphery of the cells. There was significant increase in the thickness of mitral cell layer and number of the mitral cell in the propranolol treated group (p < 0.05).

This study showed morphological and quantitative changes in the olfactory bulb in response to treatment with propranolol, hence it has implications in odour induced learning.