بر عضله صاف ناي خرگوش C.C.K بررسي اثرات كوله سيستوكينين

THE EFFECT OF CHOLECYSTOKININ ON ESOPHAGEAL MUSCLE OF RABBIT

There are many chemical receptors in the membrane of the tracheal smoothʹ muscle cells through which different neurotransmitters and chemical agents affect them and result in an increase or decrease of airway resistance. Bronchial constriction is a relatively increasing symptom due to air pollution , thus many investigators are trying to find the agents that are involved in bronchoconstriction. Cholecystokinin (C.C.K) is one of these agents that is released from the nerve endings in the airways , but the function of this polypeptide is not known yet. In this study isolated tracheal specimens lengthing about 5 cm were mounted in anoryan bath filled with krebs solution. Meetrical stimulations in different voltage (10-30 V) and frequencies (20- 60 Hz) were applied to the lower end of the specimens via a bipolar silver stimulatory electrode , and any altration in the tracheal length and tracheal pressure were recorded by using an isotonic transducer and a pressure transducer connected to a two channel oscilograph.To assess the effect of C.C.K on rabbits tracheal smooth muscle , different concentrations of C.C.K was added to the solution bathing theʹspecimens. Our data showed that C.C.K alone had no effect on the tracheal smooth muscle but could potentiate the effect of electrical stimulation in a voltage and frequency dependent manner. This effect was also concentrations dependent up to 10-7 molar (C.C.K) which showed the maximum effect on tracheal length and intratracheal pressure which (0.01). were increased significantly from dose of the control (Since different concentrations of C.C.K had no on tracheal smooth muscles by themselves but they augmented the responce to electrical stimulation suggest that C.C.K may act as a neuromodulator in the respiratory airways.