Effect of hypothermia on β₁‐adrenoceptor‐mediated relaxation of pig bronchus

Abstract

1 The relaxant potencies of (±)-isoprenaline and of (-)-noradrenaline (NA) in the pig isolated bronchus were increased 5.4 and 3.1 fold respectively by lowering the organ bath temperature from 37°C to 27°C, whereas the potencies of the non-catecholamine P-adrenoceptor agonists fenoterol and orciprenaline were not significantly changed. 2 At 37C, the catechol-O-methyl transferase (COMT) inhibitor U-0521 (30 LM), caused a 7.2 fold increase in the potency of isoprenaline but had no effect on the potency of fenoterol. At 27°C the potency of isoprenaline was similar in the absence or presence of U-0521 (30 pM). Furthermore, in bronchi where extraneuronal uptake was inhibited by phenoxybenzamine, the potency of NA was not significantly altered by reducing bathing temperature from 37°C to 27°C. 3 These results suggest that the hypothermic potentiation of isoprenaline in pig bronchus resulted from inhibition of COMT or of access to COMT, rather than from sensitization of Pi-adrenoceptors.

Effect of Menopause on Pulmonary Functions: An Analysis

“…11 Estrogen and progesterone have been associated with relaxation of airway smooth muscles mediated by relaxation of bronchial muscles and widening of bronchi. 12 The bronchial epithelium and smooth muscle contain alpha 2 adrenergic receptors which cause bronchodilation and increase secretion.…”

Assessment of bronchial responsiveness on exposure to isometric exercise during different phases of menstrual cycle: A pilot study

“…Also estradiol increases the relaxant effect of catecholamines; a falling estrogen level may reduce sensitivity to catecholamine, which in turn affects the airway response. [9] Although the effect of corticosteroid hormones on bronchial smooth muscle is well established, the effect of female sex steroids has not been well studied. For women, cyclic hormonal variations can influence the aspects of health and health behavior, from smoking cessation efficacy to physiological responses to exercise.…”

Sex Steroids and Their Influence in Lung Diseases Across the Lifespan

“…Asthma incidence begins to increase in females during late adolescence—a trend seemingly evident in the adult stage (Shah and Newcomb 2018 ). Overall, literature maintains a clear link between sex steroids and asthma (Foster et al 1983 ; Beynon et al 1988 ), and puberty is associated with fundamental hormonal fluctuations in both sexes (Sanfilippo 2008 ). Studies have indicated that the trend is more common in children with mild to moderate asthma, who tend to “outgrow” their asthma during puberty and subsequently into adulthood (Blair 1995 ; Gerritsen et al 1990 ; Martin et al 1980 ).…”

“…A precedent case showcasing estrogen-induced relaxation of smooth muscle has been widely recognized in the cardiovascular arena (Montgomery et al 2003 ; Miller and Duckles 2008 ). The earliest report of experimental data on the relaxant properties of sex steroids in the lungs discussed the potentiation of isoproterenol-mediated relaxation of the porcine bronchus (Foster et al 1983 ). Our recent studies have shown a higher expression of ER (α and β) in the ASM of those with asthma than in the ASM of nonasthmatics (Aravamudan et al 2017 ).…”