The topographical basis of cholinergic transmission in guinea-pig ileum myenteric plexus

Kadlec, O.; Šeferna, I.; Ševč⌝k, J.; Somogyi, G; Vizi, E.S.

doi:10.1016/0306-4522(90)90022-v

Cited by 12 publications

(6 citation statements)

References 22 publications

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“…Our data obtained in colon are in accordance with experiments performed in recto-anal region (Radomirov et al 2009) and small intestine (Spencer et al 2000, Ivancheva and showing that the contractions of longitudinal and circular muscles induced by electrical or mucosal brush stimulation applied anally to the recording point were higher as compared to the responses to orally applied activation. The ascending and descending reflex motor responses in both longitudinal and circular muscles decreased with the increase of the distance between the stimulation site and recording points which supports the view that the propagation of electrically-evoked excitation in nerve structures depends on the distance from the application of stimulation (Kadlec et al 1990).…”

Section: Discussionsupporting

confidence: 78%

Functional Coordination of Motor Activity in Colonic Smooth Muscles in Rat Experimental Model

Nedialkova

Stavreva²,

Negrev³

et al. 2011

Physiol Res

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Spontaneous and electrically-elicited motor activity was recorded by triple organ bath in rat segment-model preparation as display of excitation of local nerve networks and ascending or descending reflex pathways underlying contractile potency and functional coordination of colonic longitudinal and circular muscles. Spontaneous high-amplitude contractions, but not relaxations, appeared synchronously in both muscles. Electrical field stimulation applied to proximal or distal part of segments elicited both tetrodotoxin (0.1 µM)-sensitive local motor responses of the stimulated part and ascending or descending motor responses of the contralateral, nonstimulated part of the preparations. Contractions characterized the local response of longitudinal muscle. The circular muscle responded with relaxation followed by contraction. Synchronous ascending contractions and descending contraction of the longitudinal muscle and relaxation followed by contraction of the circular muscle were observed when the middle part of segments was stimulated, thus indicating that locally-induced nerve excitation propagated via intrinsic ascending or descending nerve pathways that could be synchronously coactivated by one and the same stimulus. The ascending motor responses were more pronounced and the motor responses of longitudinal muscle were expressed more than those of circular muscle suggesting an essential role of ascending reflex pathways and longitudinal muscle in the coordinated motor activity of colon.

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Section: Discussionsupporting

confidence: 78%

Functional Coordination of Motor Activity in Colonic Smooth Muscles in Rat Experimental Model

Nedialkova

Stavreva²,

Negrev³

et al. 2011

Physiol Res

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“…The amplitude of electrically-elicited descending responses of the anal canal was less expressed as compared to the electrically-induced modular responses. This observation is in agreement with the view that the propagation of electrically-evoked excitation in the nerve structures depends on the distance from the application of stimulation [28].…”

Section: Discussionsupporting

confidence: 92%

Modular and functionally-different descending recto-anal motor pathways in a rat model

et al. 2011

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We evaluated the motor responses in recto-anal preparations obtained from rats, in terms of the excitation displayed by modules of nerve networks and descending distally directed pathways, when subjected to the mechanographic on-line technique, a partitioned organ bath, electrical stimulation (EFS, 0.8 ms, 5 Hz) and distension. EFS elicited modular contractions, which increased in amplitude distally, in circular muscle rings isolated from the proximal, middle or distal rectum. The modular responses of the internal anal sphincter or anal canal were relaxation or contraction, respectively. The application of EFS to the distal rectum induced a descending contractile response in the anal canal (5.24±0.34 mN), while distension by balloon evoked a descending response consisting of contraction (1.72±0.20 mN) followed by relaxation (3.42±0.24 mN). The responses were sensitive to tetrodotoxin. Atropine considerably depressed the contractions in all preparations. Whether or not atropine was present, L-NNA increased the excitatory responses, while L-arginine decreased the contractions and extended the relaxation of internal anal sphincter and anal canal. The results suggest that excitatory neurotransmission(s) expressed in the distal rectum dominate modular nerve networks. Functionally-different descending pathways are involved in the motor activity of the anal canal. Stimulatory cholinergic pathways are dependent on the electrically-induced excitation, and inhibitory nitrergic pathways are sensitive to distension of rectal wall.

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“…The postsynaptic site of action and the difference in antagonistic potencies of pirenzepine and atropine corresponded well to their action at M2-muscarinic receptors of the smooth muscle (North et al 1985;Freedman et al 1988;Jeck et al 1988;Kilbinger & Stein 1988). The inhibitory effects of both drugs did not differ appreciably when applied either to the oral or abordl segments suggesting that their main effect was postsynaptic as it did not indicate a different presynaptic arrangement in the respective segments (Kadlec et al 1987(Kadlec et al , 1990b.…”

Section: Synaptic Effectsmentioning

confidence: 57%

“…This is in accord with our previous results showing that the addition of opiate ligands and noradrenaline to the middle segment also affected invasion by nerve action potentials of the aboral segment only when varicose cholinergic terminals were present in the middle segment; such conditions were fulfilled with the 10 mm wide middle segment (Kadlec et al 1985). Thus in our experimental arrangement the addition of drugs to the middle segment probably affected varicose cholinergic terminals and not preterminal axons (Kadlec et al 1987(Kadlec et al , 1990b.…”

Section: Mechanism Of Muscarinic Facilitationmentioning

confidence: 75%

Non-synaptic Cholinergic Modulation of Neurogenic Twitches of the Guinea-pig Ileum

Kadlec

Hynie

Mašek

et al. 1991

Journal of Pharmacy and Pharmacology

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The effect of cholinergic and anticholinergic compounds on conduction of neuronal excitation has been studied in myenteric plexus-longitudinal muscle strips from the guinea-pig ileum. A preparation in a special triple bath was drawn through two rubber membranes dividing the strip into three segments. Neurogenic stimulation of the oral segment set up nerve action potentials propagating aborally across the middle segment (10 mm) so that the aboral segment might be also invaded, eventually. Drugs were added to the middle segment to affect neuronal propagation (non-synaptic effects) which was monitored by twitch height of the aboral segment. The application of acetylcholine to the middle segment augmented aboral twitches. The effects of nicotine, pilocarpine and oxotremorine were selectively blocked by (+)-tubocurarine, pirenzepine and atropine, respectively. The effect of acetylcholine was suppressed by pirenzepine and atropine and mimicked by doubling of KCl concentration. The effect of acetylcholine may be thus explained by the facilitated propagation of nerve action potentials in partially depolarized cholinergic terminals via stimulation of muscarinic receptors. The adenylate cyclase system is not directly involved in the mechanism of muscarinic facilitation of neuronal propagation in the terminals; however, it may participate in the modulation of a final common effector mechanism.

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The topographical basis of cholinergic transmission in guinea-pig ileum myenteric plexus

Cited by 12 publications

References 22 publications

Functional Coordination of Motor Activity in Colonic Smooth Muscles in Rat Experimental Model

Functional Coordination of Motor Activity in Colonic Smooth Muscles in Rat Experimental Model

Modular and functionally-different descending recto-anal motor pathways in a rat model

Non-synaptic Cholinergic Modulation of Neurogenic Twitches of the Guinea-pig Ileum

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