Elektrophysiologische Untersuchungen zur normalen Spontanaktivit�t der isolierten Taenia coli des Meerschweinchens

Golenhofen, K.; Loh, D. v.

doi:10.1007/bf00592289

Cited by 57 publications

(16 citation statements)

References 32 publications

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“…With extracellular suction electrodes, their amplitudes ranged from 01 to 0-8 mV. Such type of activity is similar to that recorded from the longitudinal muscle layer of the guinea-pig caecum (Golenhofen & v. Loh, 1970) and human colon (Duthie & Kirk, 1978;Van Merwyk & Duthie, 1980) where the electrical oscillations were called pace-maker or prepotentials and slow potentials, respectively. Furthermore, with the use of intracellular micro-electrodes, a wave of depolarization lasting throughout the activity period was found to occur in the guinea-pig muscle (Golenhofen & v. Loh, 1970).…”

Section: Resultssupporting

confidence: 72%

“…This is in contrast to the circular layer where each oscillation (slow wave) with associated spikes leads to a phasic contraction. The pattern of electrical and motor activity of the longitudinal muscle is virtually identical to that recorded from the taenia of the guinea-pig caecum (Golenhofen & v. Loh, 1970), pig colon (Huizinga, Diamant & El-Sharkawy, 1982 a, b) and is probably similar to that recorded from the human taenia coli (Duthie & Kirk, 1978;Van Merwyk & Duthie, 1980 The pharmacological studies indicate that (a) the slow-wave activity of the circular muscle layer is myogenic whereas the pace-maker (prepotential) activity of the longitudinal layer requires an excitatory input (stretch and/or acetylcholine release), (b) the inhibitory innervation to both muscle layers is probably tonically active, and (c) under the in vitro conditions of these experiments, the strips release a substance which selectively inhibits spiking and contractions in the circular muscle layer. This substance may be a prostanoid.…”

Section: Discussionsupporting

confidence: 57%

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Electrical activities of the muscle layers of the canine colon.

El-Sharkawy¹

1983

The Journal of Physiology

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SUMMARY1. The spontaneous electrical and mechanical activities of the circular and longitudinal muscle layers of the canine colon were studied.2. The smooth muscle cells of the circular muscle layer exhibited regular, omnipresent myogenic slow-wave activity at a frequency ranging from 4 to 7 c/min. With intracellular micro-electrodes, the slow-wave amplitude was 21-38 mV and its duration 3-6 sec. The 'resting' membrane potential was -60 to -76 mV. Some slow waves had superimposed spike bursts on their peak depolarizations and only these were associated with phasic contractions. It is concluded that they serve a pace-maker function similar to their counterpart in the small intestine.3. The longitudinal muscle layer exhibited periods ofelectrical activity alternating with periods ofelectrical quiescence. During the activity periods electrical oscillations occurred at a frequency of c/min with spikes on top of them. Each electrical activity period was associated with a prolonged 'tonic' contraction. The duration of these periods was 30-120 sec and their frequency 0A4-1 1 period/min. This activity is similar to that recorded from the longitudinal muscle of the guinea-pig caecum despite the anatomical differences.4. The electrical activity periods of the longitudinal muscle appeared to require an excitatory input (stretch and/or acetylcholine release). Provided the strips were not excessively stretched, atropine abolished all electrical and motor activity.Stretching prolonged the electrical activity periods until they eventually fused together and the muscle developed maintained tone.5. Simultaneously recording from both layers showed that, although electrotonic spread between the two layers is probably insignificant, the activity of the two layers was co-ordinated. Only those slow waves of the circular layer that occurred during the electrical activity periods of the longitudinal layer had superimposed spikes. It is suggested that this co-ordination may indicate that the two muscle layers may be commanded by a common input from periodically active, cholinergic intramural neurones.It is proposed that the complex patterns of colonic electrical and motor activities may be explained as consisting of two major components: one arising from the longitudinal (long spike bursts, high-frequency oscillations and tonic contractions) and the other from the circular layer (slow waves, short spike and phasic contractions).T. Y. EL-SHARKA WY 7. Simultaneous electrical records from the two muscle layers and the mucosa failed to show a consistent relationship between the mucosal record and the activity ofeither layer. Caution should be exercised in the interpretation of intraluminally derived electrical recordings.

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Section: Resultssupporting

confidence: 72%

Section: Discussionsupporting

confidence: 57%

Electrical activities of the muscle layers of the canine colon.

El-Sharkawy¹

1983

The Journal of Physiology

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“…The electrical activity of the trachealis was recorded by the perfused capillary method of Golenhofen & v. Loh (1970) in conjunction with a Grass polygraph (Jetley & Weston, 1980). The time constant of the a.c. preamplifier used to record the electrical activity was set at 100 ms so that both slow potential waves and fast spike activity could be recorded.…”

Section: Extracediular Electrophysiological Recordingmentioning

confidence: 99%

“…Although the electrical changes evoked by TEA were very different from those induced by acetylcholine and histamine, the spasmogenic effects of the three drugs were of similar magnitude (Table 3). The capillary technique (Golenhofen & v. Loh, 1970) for extracellularly recording electrical activity from smooth muscle registers the compound electrical activity of many cells beneath the recording electrodes. It follows that the record obtained will only reflect the activity of individual cells providing that the cells which contribute to the record generate similar activity and in a fairly synchronous manner.…”

Section: The Effects Of Cooling and Rapid Rewarmingmentioning

confidence: 99%

Electrical Slow Waves and Tone of Guinea‐pig Isolated Trachealis Muscle: Effects of Drugs and Temperature Changes

Small

1982

British J Pharmacology

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Simultaneous recordings of electrical and mechanical activity have been made from guinea‐pig isolated trachealis muscle. Electrical activity was recorded both by extracellular and intracellular techniques. Extracellular studies showed that the spontaneous development of tone was accompanied by electrical slow waves which frequently exhibited pronounced waxing and waning. Intracellular recording confirmed the discharge of these slow waves in individual cells. Extracellularly‐recorded slow waves were often of greatest amplitude while the tissue was developing rather than maintaining tension. Some tissues became electrically quiescent on reaching peak tone. Cooling to 27.5°C caused some relaxation. Slow wave amplitude and frequency fell, slow waves eventually being abolished. Subsequent rapid rewarming initially evoked a more profound relaxation. An intense discharge of slow waves then occurred as the tension rapidly rose again towards the pre‐cooling value. Sodium nitrite, (−)‐isoprenaline, adenosine and adenosine triphosphate (ATP) each evoked relaxation and reduced the frequency and amplitude of slow waves. High concentrations of these agents often abolished slow waves. The actions of these drugs were reversible. Treatment with methoxyverapamil (D600) 1 μmol/l for 15 min abolished slow wave activity but only evoked partial relaxation of the tissue. Acetylcholine, histamine and tetraethylammonium (TEA) each evoked contraction, but TEA was unique in consistently promoting slow waves and (in high concentration) spike activity. Spasm evoked by acetylcholine and histamine did not usually involve the initiation or promotion of slow waves. Indeed in appropriate concentration these two agents always suppressed slow wave activity. The actions of the spasmogens were reversible. It is concluded that the smooth muscle cells of the trachealis are electrically coupled. While co‐ordinated slow wave activity is associated with the spontaneous development of tension in trachealis, it may not be necessary for the maintenance of the major part of the spontaneous tension exhibited by the tissue or for the spasm evoked by histamine or acetylcholine. Slow wave promotion by TEA suggests that the tissue may have a high resting potassium conductance which normally attenuates the slow waves. Slow waves may be suppressed by a variety of drugs acting by different mechanisms. Since D600 suppresses slow waves of the trachealis the mechanisms underlying the waves may be similar to those underlying spike activity in other smooth muscles.

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“…Antagonists were added to the reservoirs of PSS 30 min before re-exposure to noradrenaline in the continuing presence of the antagonist. Extracellular recording The perfused capillary method of Golenhofen & v. Loh (1970) In bicarbonate-PSS, both D600 (0.01 to 1 jmol/l) and nifedipine (0.001 to 0.1 ,umol/l) produced a concentration-dependent reduction in the responses to noradrenaline whilst sodium nitroprusside (0.1 to 10 jtmol/l) had no effect ( Figure 1). Identical results were obtained with MOPS-PSS.…”

Section: Electrophysiological Experimentsmentioning

confidence: 99%

Some Effects of Sodium Nitroprusside, Methoxyverapamil (D600) and Nifedipine on Rat Portal Vein

Jetley

Weston

1980

British J Pharmacology

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1The effects of methoxyverapamil (D600), nifedipine and sodium nitroprusside on noradrenalineinduced electrical and mechanical activity in rat portal vein have been examined. 2 D600 and nifedipine produced a concentration-dependent reduction in mechanical responses to noradrenaline whilst sodium nitroprusside had no effect. The effects of D600 and nifedipine were reversed by increasing the extracellular calcium concentration. 3 The mechano-inhibitory effects of D600 were accompanied by a marked reduction in electrical activity with some evidence of electromechanical uncoupling. 4 The mechano-inhibitory effects of nifedipine were associated with considerable electromechanical uncoupling. 5It is concluded that in the concentrations used, D600 acts primarily by inhibiting calcium influx with some effect on electromechanical coupling whilst nifedipine interferes mainly with the coupling process. The inactivity of sodium nitroprusside suggests that the excitation-contraction coupling process in rat portal vein is relatively simple and further studies with this tissue seem indicated.

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Elektrophysiologische Untersuchungen zur normalen Spontanaktivit�t der isolierten Taenia coli des Meerschweinchens

Cited by 57 publications

References 32 publications

Electrical activities of the muscle layers of the canine colon.

Electrical activities of the muscle layers of the canine colon.

Electrical Slow Waves and Tone of Guinea‐pig Isolated Trachealis Muscle: Effects of Drugs and Temperature Changes

Some Effects of Sodium Nitroprusside, Methoxyverapamil (D600) and Nifedipine on Rat Portal Vein

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