Metabolic correlates to pacemaker activity in the smooth muscle of guinea-pig mesotubarium
(1991) In Acta Physiologica Scandinavica 141(2). p.263-272- Abstract
- Oxygen consumption (FO2) and lactate production (Flac) were measured during spontaneous activity in the guinea-pig mesotubarium. During spontaneous contractions FO2 increased to maximally 0.270 +/- 0.025 mumol min-1g-1 (n = 23), followed by a rapid fall immediately upon relaxation. In the relaxed period (5-15 min) between spontaneous contractions FO2 continued to slowly decrease by about 25% towards a final value of 0.150 +/- 0.01 mumol min-1g-1. Flac showed no consistent variation during the relaxed period. Ouabain (10(-6)M) produced a contracture, which was abolished by the Ca2(+)-antagonist felodipine (10(-6)M). In the presence of felodipine, addition of ouabain caused depolarization and a decrease of oxygen consumption by 21% and of... (More)
- Oxygen consumption (FO2) and lactate production (Flac) were measured during spontaneous activity in the guinea-pig mesotubarium. During spontaneous contractions FO2 increased to maximally 0.270 +/- 0.025 mumol min-1g-1 (n = 23), followed by a rapid fall immediately upon relaxation. In the relaxed period (5-15 min) between spontaneous contractions FO2 continued to slowly decrease by about 25% towards a final value of 0.150 +/- 0.01 mumol min-1g-1. Flac showed no consistent variation during the relaxed period. Ouabain (10(-6)M) produced a contracture, which was abolished by the Ca2(+)-antagonist felodipine (10(-6)M). In the presence of felodipine, addition of ouabain caused depolarization and a decrease of oxygen consumption by 21% and of lactate production by 31%. Exchange of glucose in the physiological Krebs solution for beta-hydroxybutyrate did not influence spontaneous activity, while subsequent addition of cyanide (2 mM) abolished contractions and caused a hyperpolarization of 15 mV. Blockade of ATP-dependent K+ channels by addition of glibenclamide (10(-7)M) to the relaxed muscle in this situation caused spontaneous contractile activity to reappear. In glucose-containing Krebs solution glibenclamide had no effect on the spontaneous contractile and electrical activity and contractions persisted after addition of cyanide. The relaxing and hyperpolarizing effect of pinacidil could be counteracted by addition of glibenclamide. The results suggest that a decrease in electrogenic Na+/K(+)-pump activity in the course of the relaxed period between contractions could contribute to the pacemaker behaviour. ATP-dependent K+ channels, while having little influence on the spontaneous contractile activity under normal metabolic conditions, could be activated during blockade of aerobic and anaerobic metabolism, leading to inhibition of pacemaker activity. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1105939
- author
- Lydrup, M L and Hellstrand, Per LU
- organization
- publishing date
- 1991
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Acta Physiologica Scandinavica
- volume
- 141
- issue
- 2
- pages
- 263 - 272
- publisher
- Wiley-Blackwell
- external identifiers
-
- pmid:1904676
- scopus:0026060861
- ISSN
- 0001-6772
- language
- English
- LU publication?
- yes
- id
- 7be027fc-6299-4ecb-b5ea-b2a43945cdb6 (old id 1105939)
- date added to LUP
- 2016-04-01 16:25:49
- date last changed
- 2021-01-03 04:54:40
@article{7be027fc-6299-4ecb-b5ea-b2a43945cdb6,
abstract = {{Oxygen consumption (FO2) and lactate production (Flac) were measured during spontaneous activity in the guinea-pig mesotubarium. During spontaneous contractions FO2 increased to maximally 0.270 +/- 0.025 mumol min-1g-1 (n = 23), followed by a rapid fall immediately upon relaxation. In the relaxed period (5-15 min) between spontaneous contractions FO2 continued to slowly decrease by about 25% towards a final value of 0.150 +/- 0.01 mumol min-1g-1. Flac showed no consistent variation during the relaxed period. Ouabain (10(-6)M) produced a contracture, which was abolished by the Ca2(+)-antagonist felodipine (10(-6)M). In the presence of felodipine, addition of ouabain caused depolarization and a decrease of oxygen consumption by 21% and of lactate production by 31%. Exchange of glucose in the physiological Krebs solution for beta-hydroxybutyrate did not influence spontaneous activity, while subsequent addition of cyanide (2 mM) abolished contractions and caused a hyperpolarization of 15 mV. Blockade of ATP-dependent K+ channels by addition of glibenclamide (10(-7)M) to the relaxed muscle in this situation caused spontaneous contractile activity to reappear. In glucose-containing Krebs solution glibenclamide had no effect on the spontaneous contractile and electrical activity and contractions persisted after addition of cyanide. The relaxing and hyperpolarizing effect of pinacidil could be counteracted by addition of glibenclamide. The results suggest that a decrease in electrogenic Na+/K(+)-pump activity in the course of the relaxed period between contractions could contribute to the pacemaker behaviour. ATP-dependent K+ channels, while having little influence on the spontaneous contractile activity under normal metabolic conditions, could be activated during blockade of aerobic and anaerobic metabolism, leading to inhibition of pacemaker activity.}},
author = {{Lydrup, M L and Hellstrand, Per}},
issn = {{0001-6772}},
language = {{eng}},
number = {{2}},
pages = {{263--272}},
publisher = {{Wiley-Blackwell}},
series = {{Acta Physiologica Scandinavica}},
title = {{Metabolic correlates to pacemaker activity in the smooth muscle of guinea-pig mesotubarium}},
volume = {{141}},
year = {{1991}},
}