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.

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.

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.

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.

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)

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.

cAMP-dependent sulfate secretion by the rabbit distal colon: a comparison with electrogenic chloride secretion

1997 ◽  
Vol 273 (1) ◽  
pp. C148-C160 ◽  
Author(s):  
R. W. Freel ◽  
M. Hatch ◽  
N. D. Vaziri
Keyword(s):  
Short Circuit ◽  
Basolateral Membrane ◽  
Short Circuit Current ◽  
Distal Colon ◽  
Chloride Secretion ◽  
Disulfonic Acid ◽  
Cl Secretion ◽  
Cyclic Monophosphate ◽  
Anion Conductance ◽  
Flux Measurements

The ability of a Cl-secreting epithelium to support net secretion of an anion other than a halide was investigated with 35SO4 flux measurements across the isolated, short-circuited rabbit distal colon. In most experiments, 36Cl fluxes were simultaneously measured to validate the secretory capacity of the tissues. Serosal addition of dibutyryl adenosine 3',5'-cyclic monophosphate (DBcAMP, 0.5 mM) stimulated a sustained net secretion of SO4 (about -3.0 nmol.cm-2.h-1 from a 0.20 mM solution) via an increase in the serosal-to-mucosal unidirectional flux, whereas Ca ionophore A-23187 (1 microM, serosal) produced a more transient stimulation of SO4 and Cl secretion. Net adenosine 3',5'-cyclic monophosphate (cAMP)-dependent SO4 and Cl secretion were strongly voltage sensitive, principally through the potential dependence of the serosal-to-mucosal fluxes, indicating an electrogenic transport process. Symmetrical replacement of either Na, K, or Cl inhibited cAMP-dependent SO4 secretion, whereas HCO3-free buffers had no effect on SO4 secretion. Serosal bumetanide (50 microM) or furosemide (100 microM) reduced DBcAMP-stimulated SO4 and Cl secretion, whereas serosal 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid or 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid (50 microM) blocked DBcAMP-induced SO4 secretion while enhancing net Cl secretion and short-circuit current. Mucosal 5-nitro-2-(3-phenylpropylamino)benzoic acid partially inhibited SO4 secretion and completely inhibited Cl secretion. It is concluded that secretagogue-stimulated SO4 secretion, like Cl secretion, may be an electrogenic process mediated by diffusive efflux through an apical anion conductance. Cellular accumulation of SO4 across the basolateral membrane appears to be achieved by a mechanism that is distinct from that employed by Cl.

Substance P as a mediator of colonic secretory reflexes

1997 ◽  
Vol 272 (2) ◽  
pp. G238-G245 ◽  
Author(s):  
H. J. Cooke ◽  
M. Sidhu ◽  
P. Fox ◽  
Y. Z. Wang ◽  
E. M. Zimmermann
Keyword(s):  
Substance P ◽  
Messenger Rna ◽  
Short Circuit ◽  
Chronic Administration ◽  
Short Circuit Current ◽  
Distal Colon ◽  
Chloride Secretion ◽  
Intestinal Epithelial ◽  
Axon Reflex ◽  
Reflex Pathways

The role of substance P in neural reflex pathways activated by stroking was investigated in muscle-stripped segments of distal colon from guinea pigs. Stroking the mucosal surface with a brush at 1 stroke/s evoked an increase in short-circuit current (Isc) indicative of chloride secretion. The response to mucosal stroking was maximally reduced by 69-75% by the antagonist GR-82334. The agonist [Sar9,Met(O2)11] substance P caused a bumetanide-sensitive increase in Isc when added to the mucosal or serosal bath. Ablation of extrinsic afferents with acute or chronic administration of capsaicin did not alter the mucosal stroking response. Reverse transcription-polymerase chain reaction and in situ hybridization revealed the presence of neurokinin1 (NK1) receptor messenger RNA in isolated colonocytes or crypt glands. Ligand binding of 125I-Bolton-Hunter-labeled substance P was inhibited by GR-82334. The 50% inhibitory concentration was 0.84 nM. The results demonstrate a role for substance P released from capsaicin-insensitive submucosal neurons and in mucosal stroking reflexes. The presence of NK1 receptors on isolated colonocytes suggests that appropriate elements are present for axon reflex activation of intestinal epithelial cells.

Effects of the inflammatory mediator prostaglandin D2 on submucosal neurons and secretion in guinea pig colon

1994 ◽  
Vol 266 (1) ◽  
pp. G132-G139 ◽  
Author(s):  
T. Frieling ◽  
C. Rupprecht ◽  
A. B. Kroese ◽  
M. Schemann
Keyword(s):  
Guinea Pig ◽  
Ganglion Cells ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Chloride Secretion ◽  
Prostaglandin D2 ◽  
Flux Chamber ◽  
Dose Dependent Increase ◽  
Dose Dependent

Conventional flux chamber and intracellular recording methods were used to investigate the mode of action of prostaglandin D2 (PGD2) on ion transport in muscle-stripped segments of guinea pig colon and on colonic submucosal ganglion cells. Application of PGD2 resulted in a dose-dependent increase in short-circuit current that was reduced by serosal addition of bumetanide, tetrodotoxin, atropine, or piroxicam, but not hexamethonium. Application of PGD2 to submucosal neurons evoked a depolarization of the membrane potential that was associated with an enhanced spike discharge. In AH/type 2 neurons, postspike afterhyperpolarizations were reduced in amplitude and duration. The depolarizing responses to PGD2 were not affected by tetrodotoxin, indicative of a direct effect of PGD2 on the impaled neurons. Whereas fast excitatory postsynaptic potentials (EPSPs) were not affected by PGD2, slow EPSPs were reduced by a presynaptic effect, indicating presynaptic suppression of noncholinergic neurotransmitter release. The study demonstrates that PGD2 acts as a neuromodulator to evoke nerve-mediated chloride secretion, predominantly through activation of cholinergic submucosal neurons. The results further indicate that PGD2 released from lamina propria immune cells during antigenic stimulation may influence mucosal function by altering electrical behavior of submucosal neurons.

Activation of neuronal adenosine A1 receptors suppresses secretory reflexes in the guinea pig colon

1999 ◽  
Vol 276 (2) ◽  
pp. G451-G462 ◽  
Author(s):  
Helen J. Cooke ◽  
Y.-Z. Wang ◽  
C. Y. Liu ◽  
H. Zhang ◽  
F. L. Christofi
Keyword(s):  
Guinea Pig ◽  
Adenosine Deaminase ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Chloride Secretion ◽  
Nucleoside Transport ◽  
Muscularis Mucosa ◽  
Protein Gene Product ◽  
S 100 ◽  
Nucleoside Transport Inhibitor

The role of adenosine A1 receptors (A1R) in reflex-evoked short-circuit current ( I sc) indicative of chloride secretion was studied in the guinea pig colon. The A1R antagonist 8-cyclopentyltheophylline (CPT) enhanced reflex-evoked I sc. Adenosine deaminase and the nucleoside transport inhibitor S-(4-nitrobenzyl)-6-thioinosine enhanced and reduced reflex-induced I sc, respectively. The A1R agonist 2-chloro- N 6-cyclopentyladenosine (CCPA) inhibited reflex-evoked I sc at nanomolar concentrations, and its action was antagonized by CPT. In the presence of either N-acetyl-5-hydroxytryptophyl-5-hydroxytryptophan amide to block the 5-hydroxytryptamine (5-HT)-mediated pathway or piroxicam to block the prostaglandin-mediated pathway, CCPA reduced the residual reflex-evoked I sc. CCPA reduced the response to a 5-HT pulse without affecting the tetrodotoxin-insensitive I sc responses to carbachol or forskolin. Immunoreactivity for A1R was detected in the membrane (10% of neurons) and cytoplasm (90% of neurons) of neural protein gene product 9.5-immunoreactive (or S-100-negative) submucosal neurons, in glia, and in the muscularis mucosa. A1R immunoreactivity in a majority of neurons remained elevated in the cytoplasm despite preincubation with adenosine deaminase or CPT. A1R immunoreactivity colocalized in synaptophysin-immunoreactive presynaptic varicose nerve terminals. The results indicate that endogenous adenosine binding to high-affinity A1R on submucosal neurons acts as a physiological brake to suppress reflex-evoked I scindicative of chloride secretion.

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