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The effects of stress on the periphery and in the central nervous system with respect to the role of muscarinic receptors
Vařejková, Eva ; Mysliveček, Jaromír (advisor) ; Kuncová, Jitka (referee) ; Bakoš, Ján (referee)
The aim of our work was to analyse the role of muscarinic M2 receptors (M2MRs) in the organism at rest and under stress. In the experiments, changes in animals with expressed M2MRs are compared with M2KO animals who lack these receptors. The heart rate (HR) is determined by the level of the sympathetic and parasympathetic tones, the resulting HR is being the interaction of adrenergic and cholinergic receptors, which are among the receptors attached to G proteins. Their activity is influenced by structures of the autonomic nervous system with the highest centers with integrative function in the hypothalamus. The organism responds to the absence of M2MRs by decreasing the number of adrenergic receptors; heart rate in resting conditions does not change significantly. However, in restraint stress, there are differences both during the stress response and in the post-stress period (more pronounced and prolonged tachycardia). The treatment with carbachol (MR agonist) in M2KO animals induced tachycardia, strongly suggesting the presence of cardioexcitatory MRs. Ultradian heart rate rhythm is the superstructure of the circadian rhythm controlled by the suprachiasmatic nucleus. Autonomous regulation can affect other hypothalamic functions - circadian rhythms, endocrine regulation, thermoregulation,...
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