Effects of autonomic drugs on cat colonic muscle

1981 ◽  
Vol 240 (5) ◽  
pp. G361-G364 ◽  
Author(s):  
S. Anuras ◽  
J. Christensen
Keyword(s):  
Muscarinic Receptors ◽  
Longitudinal Muscle ◽  
Circular Muscle ◽  
Adrenergic Drugs ◽  
Longitudinal Strip

The cat colon was divided in vitro into four equal segments, and one transverse and one longitudinal strip (1.5 cm x 2.5 mm) was taken from each. Transverse strips contracted rhythmically, each strip generating 0.9–1.2 g force. Longitudinal strips contracted irregularly, each strip generating 11.9–16.8 g force. Acetylcholine (10(-7) to 10(-5) M) and physostigmine (10(-8) to 10(-5) M) increased frequencies in longitudinal (P less than 0.05) but not in transverse strips (P greater than 0.05) and increased amplitudes in both (P less than 0.05). Atropine (10(-8) to 10(-6) M) reduced frequencies and amplitudes in longitudinal strips (P less than 0.05) but only amplitudes in transverse strips (P less than 0.05). Phenylephrine (10(-7) to 10(-5) M) and norepinephrine (10(-7) to 10(-5) M) increased amplitudes in transverse strips (P less than 0.05) but decreased frequencies and amplitudes in longitudinal strips (P less than 0.05). Isoproterenol (10(-7) to 10(-5) M) decreased frequencies an amplitudes in both transverse and longitudinal strips (P less than 0.05). Dopamine (10(-7) to 10(-5) M) decreased amplitudes in longitudinal strips (P less than 0.05). Tetrodotoxin (10(-7) M increased amplitudes in transverse (P less than 0.05) but not in longitudinal strips (P greater than 0.05). Both layers are affected by cholinergic and adrenergic drugs. Muscarinic receptors are excitatory in both. alpha-Adrenergic stimulations result in excitation in circular muscle and inhibition in longitudinal muscle. Circular muscle is dominated by an inhibitory neural tone.

Differential inflammatory modulation of canine ileal longitudinal and circular muscle cells

1999 ◽  
Vol 277 (2) ◽  
pp. G341-G350 ◽  
Author(s):  
Xuan-Zheng Shi ◽  
Sushil K. Sarna
Keyword(s):  
Receptor Antagonist ◽  
Muscarinic Receptor ◽  
Longitudinal Muscle ◽  
Circular Muscle ◽  
Muscle Cells ◽  
Muscle Contractions ◽  
Receptor Subtypes ◽  
Relative Role

The aim of this study was to identify the subtypes of muscarinic receptors that mediate in vivo and in vitro canine ileal longitudinal muscle contractions and whether their role is modulated by inflammation. Previous studies have reported that circular muscle contractions are suppressed in ileal inflammation induced by mucosal exposure to ethanol and acetic acid. We found that inflammation had no significant effect on in vivo and in vitro spontaneous or muscarinic receptor-mediated contractions of the longitudinal muscle. The longitudinal muscle contractions were mediated primarily by the M3 receptor subtype. However, the IC50 of the M2 receptor antagonist methoctramine was only 10 times greater than that of the M3 receptor antagonist 4-DAMP in the longitudinal muscle, whereas it was 224 times greater in the circular muscle. M2receptor-coupled decrease of intracellular cAMP occurred in the longitudinal but not in the circular muscle from the normal ileum. Inflammation did not alter this coupling in the longitudinal muscle but established it in the circular muscle. In conclusion, M2 receptors may play a greater role in the mediation of longitudinal muscle contractions than circular muscle contractions. Inflammation does not alter the contractility or the relative role of muscarinic receptor subtypes in longitudinal muscle cells. However, it modulates the M2 receptor coupling to adenylate cyclase in the circular muscle.

Differential effects of [Gln4]neurotensin on circular and longitudinal muscle of dog ileum in vitro

1987 ◽  
Vol 253 (4) ◽  
pp. G566-G572
Author(s):  
M. Karaus ◽  
K. R. Prasad ◽  
S. K. Sarna ◽  
I. M. Lang
Keyword(s):  
Longitudinal Muscle ◽  
Contractile Activity ◽  
Circular Muscle ◽  
Electrical Field Stimulation ◽  
Cholinergic Nerves ◽  
Differential Effects ◽  
Dose Dependent Fashion ◽  
Dose Dependent ◽  
Muscle Contractile

We studied the effects of neurotensin analogue [Gln4]-neurotensin on isolated dog ileal longitudinal and circular muscle strips. [Gln4]neurotensin stimulated the spontaneous contractile activity of the circular muscle but inhibited that of the longitudinal muscle in a dose-dependent fashion. Hexamethonium had no effect on the spontaneous longitudinal or circular muscle contractile activity. Atropine and tetrodotoxin (TTX) both inhibited the longitudinal muscle. Atropine had no effect on the circular muscle, but TTX stimulated it. The effects of [Gln4]neurotensin on the circular muscle were reduced but not completely abolished by atropine. The inhibition of the longitudinal muscle by [Gln4]neurotensin was not reduced by any of the above antagonists but was enhanced by atropine. Electrical field stimulation (10 Hz, 100 mA) stimulated the longitudinal muscle and inhibited or stimulated the circular muscle depending on the pulse width of the stimulus. These effects were unaffected by [Gln4]neurotensin. We conclude that [Gln4]neurotensin has differential effects on isolated muscle strips of the two muscle layers in the dog ileum. It stimulates the circular muscle partially through cholinergic nerves at preganglionic sites and partially through a direct myogenic effect. [Gln4]neurotensin inhibits the spontaneous activity of the longitudinal muscle presumably by reducing the excitability of cholinergic nerves at postganglionic sites.

The sensitivity of the longitudinal and circular muscle layers of the rat's myometrium to oxytocin in vitro during pregnancy

1987 ◽  
Vol 65 (5) ◽  
pp. 773-777 ◽  
Author(s):  
D. J. Crankshaw
Keyword(s):  
Binding Site ◽  
Longitudinal Muscle ◽  
Circular Muscle ◽  
The Other ◽  
Maximum Response ◽  
Primary Process ◽  
Maximal Force ◽  
Change In The Mean ◽  
The Mean

To test the hypothesis that binding site regulation is the primary process controlling the responsiveness of the rat's myometrium to oxytocin during pregnancy, I have studied the effects of oxytocin on longitudinal and circular strips of myometrium in vitro throughout pregnancy. Longitudinal muscle was as sensitive on day 10 of pregnancy (EC50 = 1.6 nM) as it was at term (EC50 = 1.3 nM) and there was no significant change in the mean maximal force developed in response to the hormone (2.1 ± 0.9 vs. 1.5 ± 0.3 N cm−2). Circular muscle on the other hand was essentially refractory to the hormone until day 21 of pregnancy at which time its sensitivity and the maximum response were similar to those of longitudinal muscle. These results indicated that regulation of oxytocin sensitivity in the two muscle layers was temporally different, and they suggested different mechanisms. The effect of oxytocin on longitudinal muscle was not compatible with the hypothesis that changes in binding site number regulate the responsiveness of the tissue, whereas the effect on circular muscle was.

Longitudinal contractions in the duodenum: their fluid-mechanical function

1975 ◽  
Vol 228 (6) ◽  
pp. 1887-1892 ◽  
Author(s):  
J Melville ◽  
E Macagno ◽  
J Christensen
Keyword(s):  
Longitudinal Muscle ◽  
Circular Muscle ◽  
Muscle Layer ◽  
Slow Waves ◽  
Longitudinal Muscle Layer ◽  
Circular Muscle Layer ◽  
Model Flow ◽  
Displacement Wave ◽  
Marked Points

The hypothesis examined was that contractions of the longitudinal muscle layer occurin the duodenum which are independent of those of the circular muscle layer and that they induce flow of duodenal contents. A segment of opossum duodenum isolated in vitro was marked and photographed during periods of longitudinal muscle contraction, when the circular muscle layer appeared inactive. The prequency of longitudinal oscillation of the marked points was 20.5 cycles/min. The longitudinal displacement wave spread caudad with an average velocity of 3.27 cm/s. Frequency and velocity of electrical slow waves were determined in similiar duodenal segments. Slow-wave frquencywas 18.9 cycles/min. In a two-dimensional mechanical model, flow induced by simulatedlongitudinal muscle layer appear to be driven by the electrical slow waves of the duodenum. They are capable of inducing a pattern of flow in which ocntents flow betweenthe core and the periphery of the intestinal conduit.

ADRENALINE & ITS ANTAGONIST

2005 ◽  
Vol 12 (04) ◽  
pp. 420-425
Author(s):  
AFTAB TURABI ◽  
Naseer Baluch ◽  
S. SAUD HASAN ◽  
Mehar Ali ◽  
AHMED DANYAL
Keyword(s):  
Beta Blocker ◽  
Longitudinal Muscle ◽  
Classical Method ◽  
Research Work ◽  
Circular Muscle ◽  
External Source ◽  
Force Of Contraction ◽  
Alpha Blocker ◽  
Rabbit Intestine

Objective: This research work deals with the mechanism involved in determining the therapeuticpotential of adrenaline and its blockers in gastrointestinal motility. Method: The classical method of Craig & Clark wasused for obtaining the longitudinal and circular muscles strip of rabbit intestine for in-vitro studies. Each muscle stripseparately was subjected to the effect of adrenaline and its blockers. The results were recorded on polygraphapparatus. Results: The effects were recorded in vice versa fashion i.e. agonist v/s antagonist and antagonist v/sagonist on each muscle strip separately. Adrenaline had significant effect on the force of contraction of muscle strip.On addition of antagonist in the presence of agonist the effects were increased. Longitudinal muscle showed morepronounced effects i.e. 69% with beta-blocker in comparison to the effect with alpha-blocker, which was only 27%.Circular muscle showed reduction in the force of contraction with adrenaline, which was further reduced on additionof beta-blocker, whereas the effects were increased when treated with alpha-blocker. Conclusion: This studyconcluded that adrenaline released in vitro in response to sympathetic stimulation or given from external source,increases the force and reduces the rate of contraction. Hence decreases the intestinal motility due to its antispasmodiceffect. The result of this study can be utilized in the development of new drug related to G.I. motility mediated throughadrenoceptors.

Mechanics and neuropeptide responses of feline pylorus and gastric muscle in vitro

1989 ◽  
Vol 256 (5) ◽  
pp. G862-G867 ◽  
Author(s):  
A. Merlo ◽  
S. Cohen
Keyword(s):  
Substance P ◽  
Longitudinal Muscle ◽  
Circular Muscle ◽  
Optimal Length ◽  
Pyloric Ring ◽  
Tension Properties ◽  
Gastric Muscle ◽  
Inferior Portion ◽  
Superior Portion

Mechanical properties and neuropeptide responses were compared for feline pyloric and gastric muscle under isometric conditions in vitro. Total tension in antral circular muscle (0.699 +/- 0.003 kg/cm2) was less than in corpus circular (1.597 +/- 0.007 kg/cm2) or longitudinal muscle from the lesser and greater curvatures (1.256 +/- 0.009 and 1.253 +/- 0.007 kg/cm2, n greater than or equal to 55, P less than 0.05). The components of tension at optimal length were similar for all gastric muscles (P greater than 0.1). The pylorus maintained less total tension (0.335 +/- 0.003 kg/cm2) and a greater component of resting tension (75.6%) than gastric muscle (P less than 0.01). Substance P, cholecystokinin-8 (CCK-8), and neurotensin varied in potency and efficacy in circular muscle of the antrum, corpus, and inferior portion of the pyloric ring. Longitudinal muscle and the superior portion of pylorus responded poorly if at all to neuropeptides. Substance P- but not CCK-8- or neurotensin-induced contractions of gastric muscle were reduced by tetrodotoxin (TTX) and atropine (P less than 0.05). Substance P-induced pyloric contractions were TTX sensitive (P less than 0.05) but were unaffected by atropine. We concluded that 1) length-tension properties of gastric muscle are similar and distinct from the pylorus and that 2) neuropeptide efficacy varies regionally within the feline stomach and within the pylorus.

Neuropeptide responses and mechanics of the proximal and distal feline colon in vitro

1988 ◽  
Vol 255 (6) ◽  
pp. G787-G793
Author(s):  
A. Merlo ◽  
S. Cohen
Keyword(s):  
Mechanical Properties ◽  
Substance P ◽  
Longitudinal Muscle ◽  
Circular Muscle ◽  
Isometric Contractions ◽  
Active Tension ◽  
Intrinsic Properties ◽  
Cholecystokinin Octapeptide ◽  
Anatomic Region

Mechanical properties and responses to neuropeptides were compared for proximal and distal feline colonic muscle. Proximal longitudinal (PL), proximal circular (PC), distal longitudinal (DL), and distal circular (DC) muscles were studied in vitro under isometric conditions. Total tension in DL [1.636 +/- 0.009 (SE) kg/cm2] was greater than in DC (0.699 +/- 0.004 kg/cm2) or PC (0.710 +/- 0.005 kg/cm2, P less than 0.05). Longitudinal muscle developed proportionately more active tension than circular muscle at each region (80.9% in DL vs. 54.1% in DC and 77.1% in PL vs. 52.3% in PC, P less than 0.01). Neuropeptides varied in potency and efficacy. Cholecystokinin octapeptide (CCK-8) was the most potent and efficacious in PL and substance P was the most efficacious in PC muscle (P less than 0.05). Substance P was more efficacious whereas CCK-8 and neurotensin were less efficacious in PC than PL muscle (P less than 0.01). DL muscle did not respond to CCK-8. DC muscle did not respond to CCK-8 or neurotensin. Isometric contractions to each neuropeptide were insensitive to tetrodotoxin. We conclude that 1) mechanical properties of circular and longitudinal colonic muscle differ and 2) responses to neuropeptides depend on anatomic region and intrinsic properties.

Coordination of electrical activities in muscle layers of the pig colon

1987 ◽  
Vol 252 (1) ◽  
pp. G136-G142
Author(s):  
J. D. Huizinga ◽  
E. Chow ◽  
N. E. Diamant ◽  
T. Y. el-Sharkaway
Keyword(s):  
Longitudinal Muscle ◽  
Circular Muscle ◽  
Muscle Layer ◽  
Simultaneous Recording ◽  
Frequency Range ◽  
Longitudinal Muscle Layer ◽  
Circular Muscle Layer ◽  
High Level ◽  
Electrical Activities

Simultaneous recording of electrical activities from the circular and longitudinal muscle layers of the pig colon was performed in vitro to study possible coordination of activities. The electrical activity of both muscle layers consisted of electrical oscillations with superimposed spikes. The frequency range of the electrical oscillations in the circular muscle was 0.5-3.5 cycles per minute (cpm) and in the longitudinal muscle 24-42 cpm. Coordination of the activities of both muscle layers occurred consistently only after stretch or cholinergic stimulation. Then it occurred in a unique fashion. Each oscillation in the circular muscle layer occurred at the same time as the onset of a burst of oscillations in the longitudinal muscle. In addition, multiple simultaneous recordings of the electrical activities from each muscle layer were obtained showing that within the circular muscle layer electrical oscillations were phase locked in the circumferential direction and along the long axis of the colon. They appeared to propagate in either the oral or aboral direction. In tetrodotoxin (with stretch as stimulus) and also in presence of carbachol, bursts of oscillations in the longitudinal muscle layer were phase locked circumferentially (in the different taeniae) and longitudinally. This study shows that the muscle layers in the colon, which have different myogenic electrical activities, can obtain a high level of coordination.

Biphasic effect of SNP on opossum esophageal longitudinal muscle: involvement of cGMP and eicosanoids

1993 ◽  
Vol 265 (2) ◽  
pp. G403-G407 ◽  
Author(s):  
J. K. Saha ◽  
I. Hirano ◽  
R. K. Goyal
Keyword(s):  
Longitudinal Muscle ◽  
Circular Muscle ◽  
Muscle Involvement ◽  
Cyclic Monophosphate ◽  
Biphasic Effect ◽  
A Cell ◽  
Excitatory Action ◽  
Resting Tone ◽  
Ly 83583

Effects of nitric oxide (NO)-containing compounds on opossum esophageal longitudinal smooth muscle in vitro were examined. Sodium nitroprusside (SNP) and authentic NO produced a biphasic concentration-dependent relaxation-contraction sequence in the esophageal longitudinal muscle (ELM) but only a concentration-dependent relaxation of the lower esophageal sphincter (LES) and no effect in the esophageal circular muscle. A cell membrane-permeable analogue of guanosine 3',5'-cyclic monophosphate (cGMP), 8-bromoguanosine 3',5'-cyclic monophosphate (8-BrcGMP) also produced relaxation-contraction sequence in the ELM and relaxation of the LES. The guanylate cyclase inhibitors methylene blue (MB) and LY-83583 increased resting tone and had no significant effect on SNP-induced relaxation of ELM. However, they abolished the SNP- and NO-induced contraction of ELM. The cyclooxygenase inhibitor indomethacin had no effect on ELM relaxation and abolished the contractions due to SNP, NO, and 8-BrcGMP. These studies show that in the ELM 1) SNP, authentic NO, and 8-BrcGMP cause a biphasic relaxation-contraction sequence; 2) MB and LY-83583 blocked contraction but not the relaxation associated with SNP and NO; and 3) indomethacin blocked contractions but not the relaxation due to SNP, NO, and 8-BrcGMP. These results suggest that in the ELM, NO donors exert an inhibitory action that is largely cGMP independent and an excitatory action via a cGMP-dependent pathway involving endogenous eicosanoids of the cyclooxygenase pathway.

Comparison of arteries with longitudinal and circular venous muscle from the rat

1977 ◽  
Vol 232 (2) ◽  
pp. H131-H139
Author(s):  
M. L. Cohen ◽  
K. S. Wiley
Keyword(s):  
Smooth Muscle ◽  
Longitudinal Muscle ◽  
Circular Muscle ◽  
Rhythmic Activity ◽  
Vasoactive Agent ◽  
Circular Smooth Muscle ◽  
Maximal Force ◽  
Portal Veins ◽  
Muscle Responses

Rat portal, mesenteric, renal, and femoral veins possess functionally responsive circular and longitudinal smooth muscle layers in vitro. In contrast to the dominant rhythmically active longitudinal muscle of portal veins, rat longitudinal mesenteric veins lacked rhythmic activity and developed maximal force equivalent to that of mesenteric circular muscle. Renal and femoral veins exhibited predominantly circular smooth muscle responses. Rat veins must be subjected to between 1 g (renal and femoral) and 4 g (circular portal and mesenteric) of passive forse for optimal responsiveness. Contractile response to vasoactive agent including carbamylcholine, serotonin, and norepinephrine was quantitatively different among veins. Femoral veins developed greater maximal force in response to norepinephrine than to KCL, and the responses to norepinephrine were not altered by cocaine. In contrast, cocaine markedly potentiated responses to norepinephrine in portal, mesenteric, and renal veins and, to a lesser extent, in the mesenteric artery. These data demonstrate heterogeneity in rat venous tissue and suggest that neuronal innervation may markedly influence responses to norepinephrine in some, but not all, rat blood vessels.

Sign in / Sign up

Export Citation Format

Share Document