Hypothermia induces opposite response in vascular and non-vascular smooth muscles
| Autor: | Seham Mustafa |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
0106 biological sciences
Male Contraction (grammar) Vascular smooth muscle Physiology 030310 physiology Muscle Relaxation Urinary Bladder chemistry.chemical_element Isometric exercise Hypothermia Calcium 010603 evolutionary biology 01 natural sciences Biochemistry Muscle Smooth Vascular Tonic (physiology) Jejunum Rats Sprague-Dawley 03 medical and health sciences medicine.artery medicine Animals Aorta 0303 health sciences Chemistry Rats medicine.anatomical_structure Carotid Arteries Biophysics medicine.symptom General Agricultural and Biological Sciences Developmental Biology |
| Zdroj: | Journal of thermal biology. 95 |
| ISSN: | 0306-4565 |
| Popis: | Background and aim The mechanism of cooling-induced response of smooth muscles remains little understood despite the increasing importance given to it in recent years. The aim of this study was to examine the possibility of releasing a relaxant or a contractile substance during cooling from vascular and non-vascular smooth muscles. Methods Assessing the effect of cooling for two different smooth muscles together, vascular (aorta or carotid) which induced relaxation, and non-vascular (jejunum or bladder) which induced contraction. Hanging a pair of smooth muscle strips from different body organs in the same organ bath filled with Krebs solution, each strip was connected to its own transducer and recorder and stepwise cooling was applied. Recordings of isometric tension using organ-bath techniques. Results Step-wise cooling (37 °C–4 °C) of aorta and carotid smooth muscle preparations induced reproducible graded relaxation while jejunum and bladder preparations induced reproducible graded tonic contractions, inversely proportional to temperature. The responses of all the smooth muscle preparations were the same magnitude either alone or as a pair in the organ bath. Cooling abolished rhythmic smooth muscle activity of jejunum and bladder. Cooling-induced contraction was reduced by incubation in Ca2+-free solution. The effect of cooling either relaxation or contraction was not enhanced or attenuated by the presence of the two different smooth muscles with opposite response in the same organ bath, proving the absence of a relaxant or a contractile substance released during cooling. Conclusions Cooling of aorta and carotid artery induced relaxation while jejunum and bladder induced contraction. The response to cooling is inversely proportional to the temperature. There was neither a relaxant nor a contractile substance released from vascular or non-vascular smooth muscles during cooling. Our study suggested that the effect of cooling is through a thermal receptor with two subtype one in the vascular smooth muscle (deep blood vessels) which induces relaxation, and the second in non-vascular smooth muscles (non-vascular organs) that induces contraction and the responses depend on extracellular calcium. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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