Kubilay UZUNER, Yasemin AYDIN, M. Kasım ÇAYCI

Adrenergic and cholinergic responses of the tracheal smooth muscle is enhanced during estrus phase in rat

The aim of this study was to evaluate influences of hormonal changes during rat estrous cycle on airway responsiveness to bronchoconstrictor and bronchodilator agents. Materials and methods: The study was performed in 5 groups of rat tracheal smooth muscle obtained during proestrus, estrus, metestrus, and diestrus phases of the estrous cycle, as well as the ovariectomized group (n:8/group). Cumulative acetylcholine contractions ranging from 10-8 to 10-3 M bath doses and the cumulative isoproterenol relaxations ranging from 10-8 to 10-3 M precontracted with 10-5 M of acetylcholine were recorded on isolated tracheas placed in a computerized tissue bath system. Results: Acetylcholine-induced contractions ranging from 10-5 to 10-3 M were significantly enhanced dose-dependently in tracheal smooth muscle from estrus rats compared to those from metestrus and ovariectomized rats. The relaxation induced by isoproterenol (10-8 -10-3 M) also significantly increased in tracheal smooth muscle precontracted with acetylcholine (10-5 M) taken from estrus rats. However, acetylcholine-induced contractility increase in tracheal smooth muscle was much more prominent than isoproterenol-induced relaxations in tracheal smooth muscle from estrus rats. Conclusion: These findings indicated that changes in estrogen and/or progesterone levels during rat estrous cycle might affect acetylcholine and isoproterenol sensitivity of the tracheal smooth muscle.

Anahtar Kelimeler:

Key words: Acetylcholine, estradiol, estrous cycle, isoproterenol, tracheal smooth muscle

Adrenergic and cholinergic responses of the tracheal smooth muscle is enhanced during estrus phase in rat

Keywords:

Key words: Acetylcholine, estradiol, estrous cycle, isoproterenol, tracheal smooth muscle,

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González-Arenas, A., Villamar-Cruz, O., Guerra-Araiza, C., Camacho-Arroyo, I. Regulation of progesterone receptor isoforms expression by sex steroids in the rat lung. J Steroid Biochem Mol Biol 2003; 85: 25–31.
González-Arenas A, Neri-Gomez T, Guerra-Araiza C, Camacho-Arroyo I. Sexual dimorphism in the content of progesterone and estrogen receptors and their cofactors in the lung of adult rats. Steroids 2004; 69: 351–6.
Troisi RJ, Speizer FE, Willett WC, Trichopoulos D, Rosner B. Menopause, postmenopausal estrogen preparations, and the risk of adult-onset asthma. A prospective cohort study. Am J Respir Crit Care Med 1995; 152: 1183-8.
Lieberman D, Kopernic G, Porath A, Levitas E, Lazer S, Heimer D. Influence of estrogen replacement therapy on airway reactivity. Respiration 1995; 62: 205-8.
Myers JR, Sherman CB. Should supplemental estrogens be used as steroid-sparing agents in asthmatic women? Chest 1994; 106: 318-9.
Degano B, Prevost MC, Berger P, Molimard M, Pontier S, Rami J et al. Estradiol decreases the acetylcholine-elicited airway reactivity in ovariectomized rats through an increase in epithelial acetylcholinesterase activity. Am J Respir Crit Care Med 2001; 164: 1849-54.
Marcondes FK, Bianchi FJ, Tanno AP. Determination of the estrous cycle phases of rats: some helpful considerations. Braz J Biol 2002; 62: 609-14.
Butcher RL, Collins WE, Fugo NW. Plasma concentration of LH, FSH, prolactin, progesterone and estradiol-17β throughout the 4-day estrous cycle of the rat. Endocrinology 1974; 94: 1704- 8.
Smith MS, Freeman ME, Neill J. The control of progesterone secretion during the estrous cycle and early pseudopregnancy in the rat: Prolactin, gonadotropin and steroid levels associated with rescue of the corpus luteum of pseudopregnancy. Endocrinology 1975; 96: 219-26.
Depaolo LV, Masoro EJ. Endocrine hormones in laboratory animals. In: Loeb WF, Quimby FW, editors. The clinical chemistry of laboratory animals. 1st ed. Oxford: Pergamon Press; 1989. p. 279-308.
Degano B, Mourlanette P, Valmary S, Pontier S, Prevost MC, Escamilla R. Differential effects of low and high-dose estradiol on airway reactivity in ovariectomized rats. Respir Physiol Neurobiol 2003; 138: 265-74.
Medlock KL, Forrester TM, Sheehan DM. Short-term effects of physiological and pharmacological doses of estradiol on estrogen receptor and uterine growth. J Recept Res 1991; 11: 743-56.
Levin RM, Shofer FS, Wein AJ. Estrogen-induced alterations in the autonomic responses of the rabbit urinary bladder. J Pharmacol Exp Ther 1980; 215: 614-8.
Wilkinson M, Herdon H, Pearce M, Wilson C. Radioligand binding studies on hypothalamic noradrenergic receptors during the estrous cycle or after steroid injection in ovariectomized rats. Brain Res 1979; 168: 652-5.