PRELIMINARY SCREENING OF AQUEOUS EXTRACT OF CASUARINA EQUISETIFOLIA INFLORESCENCE ON ISOLATED CHICK INTESTINE AND FROG RECTUS ABDOMINUS MUSCLE FOR IDENTIFICATION OF MUSCARINIC RECEPTORS ACTIVITY

O. Umamaheswar Rao*, M. Chinna Eswaraiah and M. C. Prabhakar

ABSTRACT

Isolated tissue bath experiments are a classical pharmacological tool for evaluating concentration-response relationships in a myriad of contractile tissues. While this technique has been implemented for over 100 years, the versatility, simplicity and reproducibility of these experiments help it to remain an indispensable tool for pharmacologists and physiologists alike. The present experiments were undertaken to justify the use of an aqueous extract of inflorescence of Casuarina equisetifolia, Family: Casuarinaceae, on Acetylcholine (Ach) induced contraction on isolated frog rectus abdominus muscle and isolated chick Intestines. The log dose of Acetylcholine contractile responses were recorded on kymograph paper until the ceiling response was obtained. In both the tissues, the extract potentiates the sub-maximal dose of Ach contractions. The sub-maximal dose of Ach (without extract) was repeatedly added till the original response was obtained. Also, in the intestine preparation, 1mg concentration of extract was heated at 800C in the water bath and cooled, then immediately added into the organ bath contained a physiological solution and allow it to act for 1min, then added the sub-maximal dose of Ach. The potentiating responses were observed after heating of the extract. Repeated the same for reproducibility of the results. The inference drawn from these experiments, the aqueous extract of inflorescence of Casuarina equisetifolia potentiate the Ach induced contractions and it was reversible and the extract is thermostable. It indicates that the extract may act on the nicotinic acetylcholine receptors (nAChRs) as well as muscarinic acetylcholine receptors (mAChRs).

Keywords: Acetylcholine, Aqueous Extract of Inflorescence, Casuarina Equisetifolia, Intestinal Smooth Muscle and Skeletal Muscle.