Role of Ca2+ in non-cholinergic, non-adrenergic responses to nerve stimulation of the guinea-pig small intestine

1982 ◽  
Vol 319 (2) ◽  
pp. 115-120 ◽  
Author(s):  
V. Bauer ◽  
O. Matušák ◽  
M. Bezeková ◽  
L. Beneš ◽  
H. Kuriyama
Keyword(s):  
Small Intestine ◽  
Guinea Pig ◽  
Nerve Stimulation ◽  
Stimulation Of

Protective role of epithelium in the guinea pig airway

1989 ◽  
Vol 66 (4) ◽  
pp. 1547-1552 ◽  
Author(s):  
M. Munakata ◽  
I. Huang ◽  
W. Mitzner ◽  
H. Menkes
Keyword(s):  
Guinea Pig ◽  
Protective Role ◽  
Airway Epithelial ◽  
Serosal Side ◽  
Epithelial Surface ◽  
Airway Responses ◽  
Airway Tone ◽  
Stimulation Of

We developed an in vitro system to assess the role of the epithelium in regulating airway tone using the intact guinea pig trachea (J. Appl. Physiol. 64: 466–471, 1988). This method allows us to study the response of the airway when its inner epithelial surface or its outer serosal surface is stimulated independently. Using this system we evaluated how the presence of intact epithelium can affect pharmacological responsiveness. We first examined responses of tracheae with intact epithelium to histamine, acetylcholine, and hypertonic KCl when stimulated from the epithelial or serosal side. We then examined the effect of epithelial denudation on the responses to these agonists. With an intact epithelium, stimulation of the inner epithelial side always caused significantly smaller changes in diameter than stimulation of the outer serosal side. After mechanical denudation of the epithelium, these differences were almost completely abolished. In the absence of intact epithelium, the trachea was 35-fold more sensitive to histamine and 115-fold more sensitive to acetylcholine when these agents were applied to the inner epithelial side. In addition, the presence of an intact epithelium almost completely inhibited any response to epithelial side challenge with hypertonic KCl. These results indicate that the airway epithelial layer has a potent protective role in airway responses to luminal side stimuli, leading us to speculate that changes in airway reactivity measured in various conditions including asthma may result in part from changes in epithelial function.

Some species differences in the intrinsic factor stimulation of B12 uptake by small intestine in vitro

1959 ◽  
Vol 197 (4) ◽  
pp. 926-928 ◽  
Author(s):  
T. Hastings Wilson ◽  
Elliott W. Strauss
Keyword(s):  
Small Intestine ◽  
Guinea Pig ◽  
Species Differences ◽  
Intrinsic Factor ◽  
Vitamin B ◽  
Guinea Pig Ileum ◽  
Rat Intestine ◽  
Intrinsic Factors ◽  
Stimulation Of

Sacs of everted small intestine from a variety of animals were incubated in bicarbonate-saline containing vitamin B12 with and without intrinsic factor (IF). B12 uptake by rat intestine was stimulated only by its own intrinsic factor. Guinea pig ileum responded to all intrinsic factors tested (guinea pig, rat, hog, hamster, human being and rabbit). The intestines of hamster and rabbit were intermediate in specificity, responding to some, but not all, of the IF preparations. Species differences occur in both the intestine and intrinsic factor preparations. The guinea pig ileum was suggested as a possible assay for both hog and human IF.

Effect of food intake on intestinal cholesterol synthesis in rats

1986 ◽  
Vol 251 (3) ◽  
pp. G362-G369
Author(s):  
K. R. Feingold ◽  
G. Zsigmond ◽  
S. R. Lear ◽  
A. H. Moser
Keyword(s):  
Small Intestine ◽  
Food Intake ◽  
Direct Contact ◽  
Cholesterol Synthesis ◽  
Third Trimester ◽  
Increase Food Intake ◽  
Effect Of Food ◽  
Small Intestinal ◽  
Stimulation Of

The mechanism by which diabetes results in an increase in small intestinal cholesterol synthesis is unknown. Previous studies have demonstrated that limiting food intake prevents the increase in intestinal cholesterol synthesis, and it has therefore been proposed that the stimulation of cholesterol synthesis in the small intestine is secondary to the hyperphagia that is associated with poorly controlled diabetes. To shed further light on the role of hyperphagia we have studied the effect on cholesterol synthesis of a variety of conditions that increase food intake. In third-trimester pregnant animals, lactating animals, obese animals, and in animals infused intragastrically with 16 g glucose/day vs. 8 g glucose/day, we have observed that an increase in food intake is associated with an increase in small intestinal cholesterol synthesis. Furthermore, these findings support the hypothesis that hyperphagia is the chief stimulus for the increase in cholesterol synthesis in the small intestine of diabetic animals. Additional studies have demonstrated that simply increasing the bulk of food ingested by adding Alphacel to the diet does not alter cholesterol synthesis in the small intestine. Lastly, in animals in whom Thiry fistulas were surgically constructed we observed that cholesterol synthesis is increased in the diabetic animals in both the segment of the small intestine in contact with the food stream and the segment of the small intestine that is excluded from contact. This observation suggests that the direct contact of the intestinal mucosa with caloric sources is not the sole trigger for increasing small intestinal cholesterol synthesis in hyperphagic diabetic animals.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Innervation of enteric mast cells by primary spinal afferents in guinea pig and human small intestine

2014 ◽  
Vol 307 (7) ◽  
pp. G719-G731 ◽  
Author(s):  
Guo-Du Wang ◽  
Xi-Yu Wang ◽  
Sumei Liu ◽  
Meihua Qu ◽  
Yun Xia ◽  
...  
Keyword(s):  
Nervous System ◽  
Mast Cell ◽  
Small Intestine ◽  
Electrical Stimulation ◽  
Mast Cells ◽  
Guinea Pig ◽  
Mast Cell Protease ◽  
Human Small Intestine ◽  
Neurokinin 1 ◽  
Stimulation Of

Mast cells express the substance P (SP) neurokinin 1 receptor and the calcitonin gene-related peptide (CGRP) receptor in guinea pig and human small intestine. Enzyme-linked immunoassay showed that activation of intramural afferents by antidromic electrical stimulation or by capsaicin released SP and CGRP from human and guinea pig intestinal segments. Electrical stimulation of the afferents evoked slow excitatory postsynaptic potentials (EPSPs) in the enteric nervous system. The slow EPSPs were mediated by tachykinin neurokinin 1 and CGRP receptors. Capsaicin evoked slow EPSP-like responses that were suppressed by antagonists for protease-activated receptor 2. Afferent stimulation evoked slow EPSP-like excitation that was suppressed by mast cell-stabilizing drugs. Histamine and mast cell protease II were released by 1) exposure to SP or CGRP, 2) capsaicin, 3) compound 48/80, 4) elevation of mast cell Ca2+ by ionophore A23187, and 5) antidromic electrical stimulation of afferents. The mast cell stabilizers cromolyn and doxantrazole suppressed release of protease II and histamine when evoked by SP, CGRP, capsaicin, A23187, electrical stimulation of afferents, or compound 48/80. Neural blockade by tetrodotoxin prevented mast cell protease II release in response to antidromic electrical stimulation of mesenteric afferents. The results support a hypothesis that afferent innervation of enteric mast cells releases histamine and mast cell protease II, both of which are known to act in a diffuse paracrine manner to influence the behavior of enteric nervous system neurons and to elevate the sensitivity of spinal afferent terminals.

An intracellular study of myenteric neurons in the mouse colon

1986 ◽  
Vol 55 (6) ◽  
pp. 1395-1406 ◽  
Author(s):  
K. Furukawa ◽  
G. S. Taylor ◽  
R. A. Bywater
Keyword(s):  
Small Intestine ◽  
Guinea Pig ◽  
Nerve Stimulation ◽  
Circular Muscle ◽  
Input Resistance ◽  
Synaptic Activity ◽  
Myenteric Neurons ◽  
Mouse Colon ◽  
Long Latency ◽  
Wide Range

Intracellular recordings have been made in vitro from the myenteric neurons of the distal colon of normal littermates of the piebald-lethal mouse. Out of a total of 90 neurons, 82 were classified as S/type 1 cells and 8 as AH/type 2 cells. Seventy-eight out of 82 S cells showed spontaneous fast excitatory postsynaptic potentials (EPSPs) sensitive to d-tubocurarine (dTC, 280 microM), and 22 S cells showed spontaneous action potentials (APs). Six S cells and 1 AH cell showed spontaneous nonnicotinic slow depolarizations associated with an increase in the input resistance of the cells; during the spontaneous slow depolarization in the S cells there was an increase in the frequency of nicotinic fast EPSPs and APs. Three S cells showed spontaneously occurring regular oscillations of the membrane potential (approximately mV in amplitude and approximately 4/min). Transmural nerve stimulation produced fast EPSPs with a wide range of latencies (3 ms to 20 s) in S cells; the fast EPSPs were blocked by dTC (280 microM) or solutions containing low Ca2+ (0.25 mM) and high Mg2+ (12 mM) but not by atropine (ATR, 14 microM). Single or repetitive transmural stimulation produced slow EPSPs in 24 S cells and 3 AH cells; these were not blocked by dTC (280 microM) nor ATR (14 microM). During the slow EPSPs there was an increase in the input resistance of the cells. In those S cells that showed slow EPSPs there were many long-latency fast EPSPs; long-latency fast EPSPs were also observed in 11 other S cells that did not show a slow EPSP following repetitive transmural nerve stimulation. Long-latency fast EPSPs may be related to the firing of other neurons during their slow EPSPs. The myenteric neurons in the mouse colon have similar properties to the myenteric neurons in the guinea pig small intestine. However, the colonic myenteric neurons show more ongoing synaptic activity and more prolonged activity after nerve stimulation than myenteric neurons in the guinea pig small intestine. This activity may be due to regional differences, species differences, or preparation differences (in this study the myenteric plexus was adherent to the underlying circular muscle layer).

Role of corticobulbar projection neurons in cortically induced rhythmical masticatory jaw-opening movement in the guinea pig

1986 ◽  
Vol 55 (4) ◽  
pp. 826-845 ◽  
Author(s):  
S. Nozaki ◽  
A. Iriki ◽  
Y. Nakamura
Keyword(s):  
Guinea Pig ◽  
Field Potential ◽  
Pyramidal Cells ◽  
Contralateral Side ◽  
Repetitive Stimulation ◽  
Projection Neurons ◽  
Nucleus Reticularis ◽  
Negative Field ◽  
Stimulation Of

The role of the pyramidal tract (PT) in the induction of the rhythmical masticatory activity (RMA) of the anterior digastric motoneurons by repetitive stimulation of the cortical masticatory area (CMA) was studied in the ketamine-anesthetized guinea pig. The coronal section of the medial brain stem at the pontine level did not show any effect on the cortically induced RMA in the digastric EMG, as long as the majority of the PT fibers was spared of the section. In contrast, unilateral section of the PT at the pontine level abolished the RMA in the digastric EMG induced by repetitive stimulation of the ipsilateral CMA, while that induced by the contralateral CMA stimulation was not affected by the PT section. The threshold of repetitive PT stimulation for induction of the RMA of the digastric EMG was much higher at the levels caudal to the facial nucleus than that at more rostral levels, and no RMA was induced by the PT stimulation at the caudal bulbar levels even at the supramaximal intensities for RMA induction of the PT stimulation at more rostral levels. Single shocks applied to the PT at the caudal bulbar levels did not evoke any antidromic field potential in the CMA. Single shocks applied to the CMA evoked a negative field potential in the medial bulbar reticular formation (MBRF) mainly on the contralateral side after a monosynaptic latency, which was largest in amplitude in the region including the most dorsal portion of the nucleus reticularis paragigantocellularis and the area dorsally adjacent to it (dPGC). Stimulation of the oral portion of the nucleus reticularis gigantocellularis (GC) evoked an antidromic negative field potential in the ipsilateral dPGC. Intracellular recording from neurons in the dPGC demonstrated that neurons were located in the dPGC that responded with EPSPs after a monosynaptic latency to single shocks applied to the contralateral CMA and with antidromic spike potentials to stimulation of the oral portion of the ipsilateral GC (GCo). Single shocks applied to the dPGC evoked antidromic field potential in the area in the contralateral cerebral cortex corresponding with the CMA. Injection of horseradish peroxidase (HRP) into the dPGC on one side retrogradely labeled the pyramidal cells with HRP bilaterally in the cerebral cortical area corresponding with the CMA. The number and density of the labeled cells on the contralateral side far exceeded those on the ipsilateral side.(ABSTRACT TRUNCATED AT 400 WORDS)

Sign in / Sign up

Export Citation Format

Share Document