The relationship between M3 cholinergic receptor agonist (carbachol) hyperstimulation-induced pancreatic acinar cellular injury and trypsinogen activation or NF-kappaB activation in rats was studied in vitro. Rat pancreatic acinar cells were isolated, cultured and treated with carbachol, the active protease inhibitor (pefabloc), and NF-kappaB inhibitor (PDTC) in vitro. Intracellular trypsin activity was measured by using a fluorogenic substrate. The cellular injury was evaluated by measuring the leakage of LDH from pancreatic acinar cells. The results showed that as compared with control group, 10(-3) mol/L carbachol induced a significant increase of the intracellular trypsin activity and the leakage of LDH from pancreatic acinar cells. Pretreatment with 2 mmol/L pefabloc could significantly decrease the activity of trypsin and the leakage of LDH from pancreatic acinar cells (P < 0.01) following the treatment with a high concentration of carbachol (10(-3) mol/L) in vitro. The addition of 10(-2) mol/L PDTC didn't result in a significant decrease in the activity of trypsin and the leakage of LDH from pancreatic acinar cells treated with a high concentration of carbachol (10(-3) mol/L) in vitro (P > 0.05). It was concluded that intracellular trypsinogen activation is likely involved in pancreatic acinar cellular injury induced by carbachol hyperstimulation in vitro. NF-kappaB activation may not be involved in pancreatic acinar cellular injury induced by carbachol hyperstimulation in vitro.
Carbachol/*pharmacology ; Cholinergic Agonists/pharmacology ; NF-kappa B/*metabolism ; Pancreas/metabolism ; Pancreas/*pathology ; Rats, Wistar ; Receptor, Muscarinic M3/agonists ; Trypsinogen/*metabolism

Animals ; Arecoline ; pharmacology ; Cholinergic Agonists ; pharmacology ; Female ; Guinea Pigs ; In Vitro Techniques ; Male ; Muscle Contraction ; drug effects ; Muscle, Smooth ; physiology ; Pyloric Antrum ; physiology ; Receptor, Muscarinic M3 ; metabolism

To investigate the mechanisms underlying the cholinergic agonist carbachol-induced cardiovascular responses, changes of renin-angiotensin system were examined in fetal hormonal systems. In the ovine fetal model under stressless condition, the cardiovascular function was recorded. Blood samples were collected before (during baseline period) and after the intravenous administration of carbachol. Simultaneously, the levels of angiotensin I (Ang I), angiotensin II (Ang II) and vasopressin in the fetal plasma were detected by immunoradiological method. Also, blood gas, plasma osmolality and electrolyte concentrations were analyzed in blood samples. Results showed that in chronically prepared ovine fetus, intravenous infusion of carbachol led to a significant decrease of heart rate (P < 0.05), and a transient decrease followed by an increase of blood pressure (P < 0.05) within 30 min. After the intravenous infusion of carbachol, blood concentrations of Ang I and Ang II in near-term ovine fetus were both significantly increased (P < 0.05); however, blood concentration of vasopressin, values of blood gas, electrolytes and plasma osmolality in near-term ovine fetus were not significantly changed (P > 0.05). Blood levels of Ang I and Ang II in the atropine (M receptor antagonist) + carbachol intravenous administration group was lower than those in the carbachol group without atropine administration (P < 0.05). In conclusion, this study indicates that the near-term changes of cardiovascular system induced by intravenous administration of carbachol in ovine fetus, such as blood pressure and heart rate, are associated with the changes of hormones of circulatory renin-angiotensin system.
Angiotensin I ; blood ; Angiotensin II ; blood ; Animals ; Blood Pressure ; Carbachol ; pharmacology ; Cholinergic Agonists ; pharmacology ; Fetus ; Heart Rate ; Renin-Angiotensin System ; Sheep ; Vasopressins ; blood

Acetylcholine ; metabolism ; physiology ; Animals ; Cholinergic Agonists ; pharmacology ; Male ; Muscle Contraction ; drug effects ; physiology ; Muscle Relaxation ; drug effects ; physiology ; Muscle, Smooth ; drug effects ; pathology ; physiopathology ; Rabbits ; Random Allocation ; Receptors, Cholinergic ; physiology ; Synaptic Transmission ; drug effects ; Urinary Bladder ; drug effects ; innervation ; physiopathology

OBJECTIVETo investigate the effects of arecoline and nicotine on the expression of human telomerase reverse transcriptase (hTERT) mRNA and protein in cultured normal human oral keratinocytes (KC).

METHODSThe experiments were divided into arecoline group, arecoline/nicotine group and control group. The hTERT mRNA and protein expression of KC was examined by reverse transcription polymerase chain reaction (RT-PCR) and Western blot.

RESULTSArecoline could induce the hTERT mRNA and protein expression of KC in a dose dependent manner, the hTERT mRNA and protein expression of KC was higher in 0.030, 0.060, 0.090 g/L arecoline group than control group (P < 0.001). Nicotine (0.025 g/L) increased hTERT mRNA and protein expression of KC induced by arecoline.

CONCLUSIONSArecoline could increase the expression of hTERT mRNA and protein in oral keratinocytes. Nicotine had a synergistic effect on arecoline. hTERT over-expression induced by arecoline and nicotine may play an important role in the malignant transformation of oral submucous fibrosis.

Arecoline ; pharmacology ; Cells, Cultured ; Cholinergic Agonists ; pharmacology ; Dose-Response Relationship, Drug ; Drug Synergism ; Ganglionic Stimulants ; pharmacology ; Humans ; Keratinocytes ; drug effects ; enzymology ; Mouth Mucosa ; enzymology ; pathology ; Nicotine ; pharmacology ; RNA, Messenger ; genetics ; metabolism ; Telomerase ; genetics ; metabolism

The effects of Arecoline (Are) on calcium mobilization were investigated. In isolated single ventricular myocyte of guinea pig, patch clamp whole cell recording techniques were used to record the current of L-type calcium channel and cytosolic Ca2+ level ([Ca2+]i) labeled with fluorescence probe Fluo-3/AM was measured under a laser scanning confocal microscope. Results revealed that Are (3-100 mumol/L) could inhibit L-type calcium current in a concentration-dependent manner and the value of IC50 was 33.73 mumol/L (n = 5). In the absence of extracellular calcium, the resting levels of [Ca2+]i was not affected by Are (n = 6, P > 0.05), but pretreatment with Are (30 mumol/L) could significantly inhibit the [Ca2+]i elevation induced by caffeine (10 mmol/L, n = 6, P < 0.01). It was concluded that Are could inhibit not only calcium influx through L-type calcium channel but also calcium release from sarcoplasmic reticulum.
Animals ; Arecoline ; pharmacology ; Biological Transport, Active ; Caffeine ; pharmacology ; Calcium ; metabolism ; Calcium Channels, L-Type ; drug effects ; metabolism ; Cell Separation ; Cholinergic Agonists ; pharmacology ; Guinea Pigs ; Heart Ventricles ; cytology ; Myocytes, Cardiac ; cytology ; metabolism ; Patch-Clamp Techniques ; Sarcoplasmic Reticulum ; metabolism

AIMTo study whether the mAchR agonist Carbachol(Cch, nonselective) causes increased contractions and L-type Ca2+ current [L(Ca(L))] in ventricular myocytes and the mechanism of these effects.

METHODSThe effect of Cch on the I(Ca(L)) and Na/Ca exchange current (I(Na/Ca) was studied in patch-clamped ventricular myocytes isolated from rat hearts and superfused with Tyrode's solution (35 degrees C, 1.8 mmol/L [Ca2+]o) and stimulated at 0.2 Hz and 1.0 Hz evoke contractions of single myocyte.

RESULTS(1) An increase of stimulation frequency decreased the contractions of myocytes(negative inotropic effects). (2) 100 micromol/L Cch increased contraction in 6 cells by 28% (delta L0.2 Hz/ delta L1.0 Hz > or = 1.25) at 1.0 Hz stimulus frequency. (3) The mAchR antagonist Atropine prevented the Cch effect. The mAchR agonist McN-A-343 (M1-selective) did not change the contractions in most of the cells. (4) 100 micromol/L Cch had no significant effect on basal I(Ca(L)), but increased the tail current density on repolarization from +10 mV to -40 mV, suggested that Cch increased I(Na/Ca).

CONCLUSIONThe increase of cell contractions by Cch is apparently mediated by M2 mAchR and eventually increased I(Na/Ca). The increase Ca2+ content of the SR is reflected by the greater magnitude of I(Na/Ca). These results provide an explanation for the increased contraction of the rat ventricular myocytes by Cch and without changes in I(Ca(L)).

Animals ; Calcium Channels, L-Type ; physiology ; Carbachol ; pharmacology ; Cholinergic Agonists ; pharmacology ; Heart Ventricles ; cytology ; Muscle Contraction ; drug effects ; Myocytes, Cardiac ; physiology ; Patch-Clamp Techniques ; Rats ; Sodium-Calcium Exchanger ; physiology

Acetylcholine ; metabolism ; Animals ; Brain ; drug effects ; metabolism ; Choline O-Acetyltransferase ; metabolism ; Cholinergic Agonists ; pharmacology ; Epithelial Cells ; metabolism ; Kidney Tubules ; cytology ; metabolism ; Lateral Ventricles ; drug effects ; Male ; Natriuresis ; Rats ; Rats, Sprague-Dawley

BACKGROUNDCa(2+) in the central nervous system plays important roles in brain physiology, including neuronal survival and regeneration in rats with injured facial motoneurons. The present research was to study the modulations of intracellular free Ca(2+) concentrations by cholinergic receptors in rat facial nucleus, and the mechanisms of the modulations.

METHODSThe fluorescence intensity of facial nucleus in Fluo-3 AM loaded acute brainstem slices was detected by applying intracellular free Ca(2+) measurement technique via confocal laser scanning microscope. The changes of fluorescence intensity of facial nucleus indicate the average changes of intracellular free Ca(2+) levels of the neurons.

RESULTSAcetylcholine was effective at increasing the fluorescence intensity of facial nucleus. Muscarine chloride induced a marked increase of fluorescence intensity in a concentration dependent fashion. The enhancement of fluorescence intensity by muscarine chloride was significantly reduced by thapsigargin (depletor of intracellular Ca(2+) store; P < 0.01), rather than Ca(2+) free artifical cerebrospinal fluid or EGTA (free Ca(2+) chelator; P > 0.05). And the increase of fluorescence intensity was also significantly inhibited by pirenzepine (M(1) subtype selective antagonist; P < 0.01) and 4-DAMP (M(3) subtype selective antagonist; P < 0.01). In addition, fluorescence intensity was markedly increased by nicotine. The enhancement of fluorescence intensity by nicotine was significantly reduced by EGTA, nifedipine (L-type voltage-gated Ca(2+) channel blocker), dihydro-beta-erythroidine (alpha4beta2 subtype selective antagonist), and in Ca(2+) free artificial cerebrospinal fluid (P < 0.01), but not in the presence of mibefradil (M-type voltage-gated Ca(2+) channel blocker) or thapsigargin (P > 0.05).

CONCLUSIONSThe data provide the evidence that muscarinic receptors may induce the increase of intracellular free Ca(2+) levels through the Ca(2+) release of intracellular Ca(2+) stores, in a manner related to M(1) and M(3) subtypes of muscarinic receptors in rat facial nucleus. Nicotine may increase intracellular free Ca(2+) concentrations via the influx of extracellular Ca(2+)+ mainly across L-type voltage-gated Ca(2+) channels, in a manner related to the alpha4beta2 subtype of nicotinic receptors.

Acetylcholine ; pharmacology ; Aniline Compounds ; administration & dosage ; Animals ; Brain Stem ; cytology ; drug effects ; metabolism ; Calcium ; metabolism ; Diamines ; pharmacology ; Facial Nerve ; cytology ; Female ; Fluorescent Dyes ; administration & dosage ; In Vitro Techniques ; Male ; Microscopy, Confocal ; Motor Neurons ; drug effects ; metabolism ; Muscarinic Agonists ; pharmacology ; Nicotine ; pharmacology ; Nicotinic Agonists ; pharmacology ; Piperidines ; pharmacology ; Pirenzepine ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Receptors, Cholinergic ; metabolism ; Receptors, Muscarinic ; metabolism ; Receptors, Nicotinic ; metabolism ; Tropicamide ; pharmacology ; Xanthenes ; administration & dosage

The effect of electroacupuncture (EA) on experimental colitis was investigated in Sprague-Dawley rats. Colitis was induced by intracolonic instillation of 4% acetic acid. EA (2 Hz, 0.05 ms, 2 V for 20min) was applied to bilateral Hoku (LI-4) and Zusanli (ST-36) on 12 hrs and 36 hrs after induction of colitis. EA-treatment significantly reduced the macroscopic damage and the myeloperoxidase activity of colonic samples at 3 days post-induction of colitis. Colitic colon showed a decreased in vitro motility. However, colonic motility of EAtreated group was not significantly different from that of normal group. The anti-inflammatory effect of EA was not inhibited by a glucocorticoid receptor antagonist, RU-486, but suppressed by a beta-adrenoceptor antagonist, propranonol. These results suggest that EA-treatment has a beneficial effect on colitis, and its anti-inflammatory effect is mediated by beta-adrenoceptor activation but not by endogenous glucocorticoiddependent mechanism.
Acetic Acid ; Adrenergic beta-Antagonists/pharmacology ; Animals ; Carbachol/pharmacology ; Cholinergic Agonists/pharmacology ; Colitis/chemically induced/enzymology/pathology/*therapy ; Electroacupuncture/*veterinary ; Enzyme Inhibitors/metabolism ; Gastrointestinal Motility/physiology ; Hormone Antagonists/pharmacology ; Male ; Mifepristone/pharmacology ; Muscle Contraction/physiology ; Muscle, Smooth/drug effects/physiology ; NG-Nitroarginine Methyl Ester/pharmacology ; Peroxidase/metabolism ; Propranolol/pharmacology ; Rats ; Rats, Sprague-Dawley