Acetylcholine release from colonic submucous neurons associated with chloride secretion in the guinea pig

1992 ◽  
Vol 262 (1) ◽  
pp. G131-G136 ◽  
Author(s):  
N. H. Javed ◽  
H. J. Cooke
Keyword(s):  
Guinea Pig ◽  
Ion Transport ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Electrical Field Stimulation ◽  
Distal Colon ◽  
Chloride Secretion ◽  
Ach Release ◽  
Response Characteristics ◽  
Flux Chambers

Electrical field stimulation of submucous neurons in the guinea pig distal colon evokes an increase in chloride secretion sensitive to cholinergic blockade. This study was undertaken in the guinea pig to determine the feasibility of measuring acetylcholine (ACh) release simultaneously with ion transport in sheets of colonic submucosa/mucosa set up in flux chambers modified for perfusion of the submucosal surface. Release of [3H]ACh was determined in the absence of cholinesterase inhibitors as the stimulus-evoked outflow of 3H from preparations preloaded with [3H]choline. [3H]ACh released in response to electrical stimulation correlated with short-circuit current at frequencies from 0.5 to 10 Hz. At 5 and 10 Hz, the stimulus-evoked release of [3H]ACh decreased during subsequent stimulation periods. The stimulus-evoked increase in [3H]ACh was attenuated by tetrodotoxin. [3H]ACh release evoked at stimulus frequencies of 0.5-10 Hz was not altered by atropine despite a reduction in short-circuit current. This study illustrates the feasibility of measuring ACh release simultaneously with ion transport in flux chambers. The results provide new information on the response characteristics of colonic submucous neurons and provide direct evidence for regulation of chloride secretion by ACh.

Neural 5-hydroxytryptamine receptors regulate chloride secretion in guinea pig distal colon

1991 ◽  
Vol 261 (5) ◽  
pp. G833-G840 ◽  
Author(s):  
H. J. Cooke ◽  
Y. Z. Wang ◽  
T. Frieling ◽  
J. D. Wood
Keyword(s):  
Guinea Pig ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Electrical Field Stimulation ◽  
Distal Colon ◽  
Chloride Secretion ◽  
Cl Secretion ◽  
Release Of Acetylcholine ◽  
Ics 205 930 ◽  
Stimulation Of

The effects of 5-hydroxytryptamine (5-HT) on epithelial short-circuit current (Isc) were determined and related to the 5-HT effects on electrical and synaptic behavior of neurons in the submucosal plexus of the guinea pig colon. 5-HT evoked a biphasic increase in Isc that was reduced by bumetanide, Cl(-)-free solutions, atropine, and mecamylamine and abolished by tetrodotoxin. The 5-HT response was mimicked by 2-methyl-5-HT, but not by 5-hydroxyindalpine, 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane, and 5-methoxytryptamine (5-MeOT). ICS 205-930 suppressed the 5-HT response. Electrical field stimulation of submucosal neurons evoked an increase in Isc indicative of Cl- secretion that was reduced by 5-MeOT and enhanced by 2-methyl-5-HT. Application of 5-HT to submucosal neurons by micropressure ejection resulted in membrane depolarization, augmented excitability, and repetitive spike discharge. The depolarization was biphasic, consisting of rapidly and slowly activating components. The rapidly activating component was suppressed by ICS 205-930. Fast excitatory postsynaptic potentials evoked by electrical stimulation of interganglionic connectives were suppressed by 5-HT and 5-MeOT. These results suggest that 5-HT activates 5-HT3 receptors, which mediate fast excitatory responses in submucosal neurons, leading to release of acetylcholine at nicotinic and muscarinic synapses and stimulation of Cl- secretion. Presynaptic inhibition suppresses acetylcholine release and results in attenuation of neurally evoked Cl- secretion.

5-HT activates nitric oxide-generating neurons to stimulate chloride secretion in guinea pig distal colon

1998 ◽  
Vol 275 (4) ◽  
pp. G829-G834 ◽  
Author(s):  
Atsukazu Kuwahara ◽  
Hirofumi Kuramoto ◽  
Makoto Kadowaki
Keyword(s):  
Nitric Oxide ◽  
Guinea Pig ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Distal Colon ◽  
Chloride Secretion ◽  
Evoked Response ◽  
Evoked Responses ◽  
No Donor ◽  
Simultaneous Application

The participation of nitric oxide (NO) in serotonin (5-hydroxytryptamine; 5-HT)-evoked chloride secretion in guinea pig distal colon was examined. Submucosal/mucosal segments were mounted in Ussing flux chambers, and an increase in short-circuit current ( I sc) was used as an index of secretion. Addition of 5-HT to the serosal side produced a concentration-dependent (10−7–10−5M) increase in I sc caused by chloride secretion. N G-nitro-l-arginine (l-NNA) significantly reduced the 5-HT-evoked early (P-1) and late (P-2) responses to 61.1 and 70.6% of control, respectively. Neurally evoked response was also inhibited by l-NNA. The NO donor sodium nitroprusside (SNP, 10−4 M) increased basal I sc mainly because of chloride secretion. The SNP-evoked response was significantly reduced by tetrodotoxin but was unchanged by atropine or indomethacin. These results suggest that the 5-HT-evoked increase in I sc is associated with an NO-generating mechanism. Atropine significantly reduced the 5-HT (10−5 M)-evoked P-1 and P-2 responses to 71.8 and 19.7% of control, respectively. Simultaneous application of atropine andl-NNA further decreased the 5-HT-evoked responses more than either drug alone; application ofl-NNA and atropine decreased the 5-HT-evoked P-1 and P-2 responses to 68.5 and 39.2% of atropine-treated tissues, respectively. These results suggest that noncholinergic components of P-1 and P-2 responses are 71.8 and 19.7% of control, respectively, and that NO components of P-1 and P-2 responses are 32 and 61%, respectively, of the noncholinergic component of the 5-HT-evoked responses. The results provide evidence that NO may participate as a noncholinergic mediator of 5-HT-evoked chloride secretion in guinea pig distal colon.

Effects of tetrodotoxin on chloride secretion in rabbit distal colon: tissue and cellular studies

1990 ◽  
Vol 258 (2) ◽  
pp. G223-G230 ◽  
Author(s):  
B. Biagi ◽  
Y. Z. Wang ◽  
H. J. Cooke
Keyword(s):  
Short Circuit ◽  
Short Circuit Current ◽  
Electrical Field Stimulation ◽  
Distal Colon ◽  
Chloride Secretion ◽  
Resting Potential ◽  
Colon Tissue ◽  
Colonic Crypts ◽  
Electrophysiological Studies ◽  
Release Of Acetylcholine

The effects of tetrodotoxin (TTX) were examined in muscle-stripped segments of rabbit distal colon and in cells of isolated colonic crypts. Electrical field stimulation (EFS) of the submucosa/mucosa evoked an increase in short-circuit current (ISC) that was due to an increase in chloride secretion. The EFS-evoked response was reduced 81% by 10(-7) M TTX and 30% by 5 X 10(-6) M atropine. Vasoactive intestinal peptide (VIP), carbachol, aminophylline, and 1,1-dimethyl-4-phenylpiperazinium increased ISC. Bumeta nide reduced the responses to neural stimulation, aminophylline, and VIP. To determine whether TTX had direct effects on crypt epithelial cells, crypts were isolated and cells were impaled with microelectrodes. Mean resting potential (Vbl) was -67 +/- 1.1 mV (n = 63). VIP and aminophylline depolarized Vbl by 34 +/- 4.6 (n = 13) and 34 +/- 3.5 mV (n = 18), respectively. TTX had no significant effect on resting Vbl or on the responses to VIP or aminophylline. We conclude that stimulation of submucosal neurons in the rabbit distal colon evokes a TTX- and bumetanide-sensitive increase in net chloride secretion that is dependent on the release of acetylcholine and other secretory neurotransmitters. Electrophysiological studies rule out a direct effect of TTX on colonic crypt cells.

H2 receptors mediate cyclical chloride secretion in guinea pig distal colon

1990 ◽  
Vol 258 (6) ◽  
pp. G887-G893 ◽  
Author(s):  
Y. Z. Wang ◽  
H. J. Cooke
Keyword(s):  
Guinea Pig ◽  
Chloride Transport ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Distal Colon ◽  
Chloride Secretion ◽  
Chloride Ions ◽  
H2 Antagonist ◽  
H2 Receptors ◽  
Peak Increase

We tested the hypothesis that histamine mediates ion secretion in the guinea pig distal colon by stimulating H2 receptors on submucosal neurons. Serosal addition of histamine evoked a transient increase in short-circuit current (Isc) followed by recurrent cyclical increases in Isc. The transient phase of the response was examined previously and was not investigated in these studies. Histamine (1.5-2.5 x 10(-5) M) evoked a peak increase in Isc of 177 +/- 25 microA/cm2 at intervals of 5 min for 1-2 h. The duration of each recurrent cycle averaged 2.1 +/- 0.3 min. The H2 agonist dimaprit evoked recurrent cycles that had larger amplitudes than those caused by histamine. In the presence of histamine or dimaprit, the amplitude of the first cycle of the response was always less than subsequent cycles, regardless of the initial concentration. The cyclical responses to histamine, 2-methylhistamine, or dimaprit were unaltered by the H1 blocker pyrilamine, were reduced by the H2 antagonist cimetidine, and were abolished by the neuronal blocker tetrodotoxin. Blockade of prostaglandin formation with piroxicam did not prevent the recurrent cycles. The recurrent cycles were inhibited by the chloride transport blocker bumetanide and by removal of chloride ions. Our results demonstrate that histamine mediates prolonged cyclical chloride secretion in the guinea pig distal colon by activating H2 receptors on submucosal neurons involved in regulation of epithelial chloride transport.

Neuroimmune interactions: role for cholinergic neurons in intestinal anaphylaxis

1992 ◽  
Vol 263 (6) ◽  
pp. G847-G852 ◽  
Author(s):  
N. H. Javed ◽  
Y. Z. Wang ◽  
H. J. Cooke
Keyword(s):  
Short Circuit ◽  
Bovine Milk ◽  
Cholinergic Neurons ◽  
Short Circuit Current ◽  
Distal Colon ◽  
Chloride Secretion ◽  
Ach Release ◽  
Immune Tissues ◽  
Beta Lactoglobulin

The role of cholinergic neurons in mediating chloride secretion in anaphylaxis was assessed in muscle-stripped segments of distal colon from guinea pigs immunized to bovine milk. beta-Lactoglobulin evoked a concentration-dependent increase in short-circuit current (Isc) in immune, but not nonimmune, tissues. The Isc response to beta-lactoglobulin was reduced by piroxicam, pyrilamine, and cimetidine. Tetrodotoxin and atropine reduced the Isc response to beta-lactoglobulin in immune animals, whereas mecamylamine and ICS 205-930 were ineffective. beta-Lactoglobulin evoked a concentration-dependent increase in acetylcholine (ACh) release in immune, but not nonimmune, animals. In immune tissues after challenge with beta-lactoglobulin, ACh release paralleled the change in Isc. Piroxicam, cimetidine plus pyrilamine, or a combination of piroxicam, cimetidine, and pyrilamine significantly reduced the release of ACh after beta-lactoglobulin challenge. Histamine, dimaprit, and prostaglandins E2 evoked an increase in ACh release. These results suggest that beta-lactoglobulin releases prostaglandins and histamine probably from mast cells. Secretory responses that occur when immune animals are challenged with beta-lactoglobulin result, in part, from activation of cholinergic neurons that utilize muscarinic synapses for transfer of signals to the epithelium.

Regional differences in the response to platelet-activating factor in rabbit colon

1992 ◽  
Vol 82 (6) ◽  
pp. 673-680 ◽  
Author(s):  
S. P. L. Travis ◽  
D. P. Jewell
Keyword(s):  
Ion Transport ◽  
Regional Differences ◽  
Chloride Transport ◽  
Short Circuit ◽  
Platelet Activating Factor ◽  
Short Circuit Current ◽  
Distal Colon ◽  
Chloride Secretion ◽  
Anion Secretion ◽  
Ussing Chambers

1. Platelet-activating factor is an inflammatory mediator related to eicosanoids which is known to stimulate anion secretion in the distal colon. Since there are regional differences in ion transport within the colon, the influence of platelet-activating factors on ion transport and epithelial permeability has been studied in rabbit caecum and distal colon mounted in Ussing chambers. 2. The effect of platelet-activating factor (1–50 nmol/l) on net electrogenic ion transport was to stimulate a biphasic increase in short-circuit current in the distal colon but not in the caecum. The platelet-activating factor-induced rise in short-circuit current was shown by ion replacement and pharmacological inhibitor studies to be consistent with chloride and bicarbonate secretion in the early phase, but with chloride secretion alone in the later phase. The effect on ion transport was specific and reversible and was enhanced by 0.25% BSA. 3. Colonic permeability, assessed by transmucosal resistance and mannitol flux, was increased by platelet-activating factor in both the distal colon and the caecum. This was consistent with an effect on platelet-activating factor on the paracellular pathway, because resistance decreased even when transcellular chloride transport was inhibited by frusemide or ion replacement. A specific platelet-activating factor antagonist (U66985) inhibited the effects of platelet-activating factor in both the distal colon and the caecum. 4. The results show that platelet-activating factor stimulates anion secretion only in the distal colon, but increases permeability in both the caecum and the distal colon.

Action of pituitary adenylate cyclase-activating polypeptide on ion transport in guinea pig distal colon

1993 ◽  
Vol 264 (3) ◽  
pp. G433-G441 ◽  
Author(s):  
A. Kuwahara ◽  
Y. Kuwahara ◽  
T. Mochizuki ◽  
N. Yanaihara
Keyword(s):  
Adenylate Cyclase ◽  
Guinea Pig ◽  
Ion Transport ◽  
Short Circuit ◽  
Distal Colon ◽  
Chloride Secretion ◽  
Dependent Manner ◽  
Evoked Responses ◽  
Concentration Dependent Manner ◽  
Pituitary Adenylate Cyclase

The aim of the present study was to investigate the action of pituitary adenylate cyclase-activating polypeptide (PACAP) on ion transport in the guinea pig distal colon. Submucosal/mucosal segments from distal colon were mounted in Ussing flux chambers, and increases in short-circuit current (Isc) were used as an index of secretion. Serosal addition of PACAP-38 and PACAP-27 produced concentration-dependent (10(-10)-10(-6) M) increases in Isc. Furosemide and chloride-free solutions significantly reduced the PACAP-evoked responses. Tetrodotoxin (TTX) completely blocked PACAP-evoked responses. Atropine significantly reduced the PACAP-evoked responses but did not abolish the responses. The results suggest that PACAP evokes chloride secretion through cholinergic and noncholinergic neural mechanism. Vasoactive intestinal polypeptide (VIP), peptide histidine-isoleucine amide, and helodermin evoked Isc in a concentration-dependent manner. Atropine reduced but did not abolish the VIP- and related peptides-evoked responses. TTX also significantly decreased the responses to higher concentrations of VIP and related peptides but did not abolish the responses. The results suggest that VIP and related peptides act on both submucosal neurons and the epithelial cell itself. VIP tachyphylaxis significantly decreased PACAP-38- and PACAP-27-evoked responses. These results provide evidence that PACAP recognizes, in some part, VIP receptors in the submucosal neurons to evoke chloride secretion.

Role of calcium in chloride secretion mediated by cAMP pathway activation in rabbit distal colon mucosa

1993 ◽  
Vol 264 (2) ◽  
pp. G252-G260 ◽  
Author(s):  
V. Calderaro ◽  
E. Chiosi ◽  
R. Greco ◽  
A. M. Spina ◽  
A. Giovane ◽  
...  
Keyword(s):  
Short Circuit ◽  
Fold Increase ◽  
Short Circuit Current ◽  
Distal Colon ◽  
Chloride Secretion ◽  
Free Medium ◽  
Cl Secretion ◽  
Pathway Activation ◽  
Flux Measurements ◽  
Pg E2

Effects of Ca2+ on adenosine 3',5'-cyclic monophosphate (cAMP)-mediated Cl- secretion were investigated in intact mucosa and isolated crypt cells of rabbit descending colon. Addition of 10 microM prostaglandin (PG)E2 or forskolin to tissues incubated in Ca(2+)-free medium increased the size of short-circuit current (Isc) and Cl- secretion as estimated by unidirectional 36Cl flux measurements (net flux = -2.31 +/- 0.24 vs. -1.22 +/- 0.10 mueq.h-1.cm-2, n = 4, P < 0.001). Addition of 10 microM PGE2 to tissues incubated in 1.2 mM Ca2+ Ringer induced a 7-fold increase in mean cAMP level, whereas it produced an 11-fold increase in tissues exposed to Ca(2+)-free medium. Membrane preparations from whole mucosa incubated in Ca(2+)-free medium displayed a cyclic nucleotide phosphodiesterase activity significantly lower than controls (18.76 +/- 0.54 vs. 31.20 +/- 0.39 pmol cAMP. mg protein-1.min-1, means +/- SE, n = 4, P < 0.001). Ca2+ removal also affected adenylate cyclase (AC) responsiveness to agonists; AC activity increased in controls by 54 and 226% after stimulation with 10 microM PGE2 and forskolin, respectively, but it increased more (77 and 325%, respectively) after incubation in Ca(2+)-free solutions.(ABSTRACT TRUNCATED AT 250 WORDS)

Chymotrypsin, ileal chloride transport, and neurotransmitters

1984 ◽  
Vol 247 (3) ◽  
pp. G253-G260 ◽  
Author(s):  
K. A. Hubel
Keyword(s):  
Cell Function ◽  
Chloride Transport ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Electrical Field Stimulation ◽  
Chloride Secretion ◽  
Target Cells ◽  
Flux Chamber ◽  
Rabbit Ileum ◽  
Electrical Field

Electrical field stimulation (EFS) depolarizes nerves and causes chloride secretion by mucosa of rabbit ileum mounted in a flux chamber. To test the hypothesis that the transmitter is a peptide, we determined whether the EFS response was prevented by the endopeptidase chymotrypsin (CT). Serosal, but not mucosal, addition of CT (200 micrograms/ml) reduced the short-circuit current (Isc) response to EFS by 90% or more. CT also reduced Cl absorption by decreasing the mucosal-to-serosal flux, but it did not affect net Na absorption. CT prevented the response to vasoactive intestinal polypeptides, but the response returned when CT activity was eliminated. The response to EFS did not return, however, implying that CT damaged cells that released transmitter or epithelial target cells. CT reduced the Isc response to serotonin by 69% and to A23187 by 10% and did not affect the theophylline response. We conclude that 1) the effects of CT on cell function limit its usefulness in identifying peptide neurotransmitters in epithelium, 2) CT irreversibly inhibits ion transport responses to EFS and to serotonin, and 3) CT reduces absorption of Cl probably by affecting a calcium pathway that modifies Cl transport.

Histamine action on guinea pig ileal mucosa

1984 ◽  
Vol 246 (4) ◽  
pp. G372-G377 ◽  
Author(s):  
H. J. Cooke ◽  
P. R. Nemeth ◽  
J. D. Wood
Keyword(s):  
Receptor Agonist ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Electrical Field Stimulation ◽  
Chloride Secretion ◽  
Evoked Response ◽  
Field Stimulation ◽  
H1 Receptor ◽  
Electrical Field ◽  
Mucosal Response

Nerve-mediated and direct actions of histamine on mucosal transport function in the guinea pig ileum were investigated. Addition of histamine to the serosal side of flat sheet preparations in Ussing chambers evoked a transient increase in base-line short-circuit current that was due primarily to an increase in active chloride secretion. The mucosal response to histamine was mimicked by the H1-receptor agonist 2-methylhistamine, but not by the H2-receptor agonist dimaprit. The histamine-evoked response was prevented by the H1-receptor blocker pyrilamine, but not by the H2-receptor antagonist cimetidine. Thirty percent of the mucosal response to histamine was inhibited by tetrodotoxin. Intracellular electrical recording showed that histamine activated AH/type 2 myenteric neurons, and this response was abolished in the presence of pyrilamine. Local anesthetic action of pyrilamine was ruled out by direct electrical recording from myenteric neurons in the presence and absence of pyrilamine. Electrical field stimulation evoked a biphasic increase in short-circuit current. Histamine and 2-methylhistamine did not alter the sustained phase of the short-circuit current response to electrical field stimulation, although pyrilamine reduced the electrically evoked response by 22%. Muscarinic blockade with atropine reduced the stimulus-evoked response by 55%. When muscarinic receptors were blocked and electrical field stimulation applied, histamine increased the stimulus-evoked mucosal response by 22.3%. These results suggest that histamine increases short-circuit current and chloride secretion by acting at H1-receptor sites on both the enteric innervation of the mucosa and on the enterocytes.

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