Anatomy of Airways Smooth Muscle

Morphology and electrophysiology of guinea-pig paratracheal neurones

“…The pathophysiology and pharmacology of asthma would, however, be incomplete without an knowledge of the effects of these agents on the excitability of the intrinsic, parasympathetic neurones of airways. In contrast to the physiology and pharmacology of the trachealis muscle and its innervation, no direct information is available about the neurones of guineapig tracheal preparations.Although the presence of ganglia in the respiratory tract has been known for many years, it is only recently that details of the innervation of guinea-pig airways have been obtained (Baluk et al, 1985; Gabella, 1989a,b, 1991;Gabella, 1994) and these reports were mainly concerned with the disposition of neurones and fibre patterns of innervation. Even information on the neurochemistry of the intrinsic neurones is relatively scanty compared with other autonomic neurones, especially myenteric and submucosal neurones.…”

Relaxation of tracheal smooth muscle is impaired in innate airway hyperresponsiveness

“…Load-independent relaxation is typical of sarcomeric muscles in which the endoplasmic reticulum is poorly developed, nonfunctional, destroyed or inhibited [30]. It is also obviously the case in ASM where endoplasmic reticulum exists only in a rudimentary form [31]. This mechanical property should be distinguished from what happens during isotonic relaxation where tK,isot,relax values are markedly influenced by the level of load (table 1).…”

Biophysical Mechanisms of Vaginal Smooth Muscle Contraction: The Role of the Membrane Potential and Ion Channels

“…The vagina is also an essential component of the female reproductive system and is responsible for providing female sexual satisfaction [ 1 ]. Smooth muscle is found throughout the body and serves a variety of functions [ 2 ]. Smooth muscle is an involuntary, non-striated muscle divided into two subgroups: single-unit and multi-unit smooth muscle.…”

“…A set of cellular and sub-cellular physiological mechanisms regulates the contractile properties of the VSM cells. Ca 2+ influx is a key determinant of VSM contraction, facilitated through voltage-dependent Ca 2+ channels (VDCC) and Ca 2+ release from intracellular stores [ 2 ]. The value of intracellular Ca 2+ concentration is modulated by the coordinated action of ion channels, neurotransmitters, and hormonal signals, leading to cyclic changes in vaginal tone and elasticity [ 6 , 8 , 9 ].…”

“…Comprehensive reviews on smooth muscle biophysics are relatively scarce within the scientific literature, likely due to the complexity and specialized nature of the topic. While research articles and studies delve into specific aspects of smooth muscle physiology and biophysics [ 2 ], a consolidated overview that encompasses all facets of smooth muscle biophysics is less common. This scarcity may stem from the interdisciplinary nature of biophysics, which requires expertise in both biology and physics [ 29 ].…”