OBJECTIVETo compare the bronchodilating effect of RR-formoterol (RR-FMT) with that of racemic formoterol (rac-FMT) on human bronchus.

METHODSHuman bronchial spiral strips (2 - 4 mm internal diameter,15 mm length) were suspended in tissue baths under resting tension of 1.0 g. The changes of tension induced by RR-FMT and rac-FMT(10 pmol x L(-1) - 3.2 micromol x L(-1)) in a cumulative concentration manner were studied under resting tension conditions or precontraction with carbamylcholine (10 micromol x L(-1)) or histamine(100 micromol x L(-1)) in human bronchus.

RESULTThe bronchodilating effect of RR-FMT was more potent than that of rac-FMT under resting condition(P<0.05). RR-FMT and rac-FMT reversed histamine or carbamylcholine-induced contraction, and the bronchodilating effect of RR-FMT was more potent than that of rac-FMT (P<0.05).

CONCLUSIONThe bronchodilating effect of RR-FMT is more potent than that of rac-FMT in both the resting condition and carbamylcholine or histamine-induced contraction in human bronchus in vitro.

Aged ; Bronchi ; drug effects ; physiology ; Bronchodilator Agents ; pharmacology ; Carbachol ; pharmacology ; Dose-Response Relationship, Drug ; Ethanolamines ; pharmacology ; Formoterol Fumarate ; Histamine ; pharmacology ; Humans ; In Vitro Techniques ; Middle Aged ; Stereoisomerism

Animals ; Botulinum Toxins, Type A ; pharmacology ; Capsaicin ; pharmacology ; Carbachol ; pharmacology ; Humans ; Keratoconjunctivitis ; surgery ; Phenylephrine ; pharmacology ; Saliva ; drug effects ; Submandibular Gland ; drug effects ; transplantation ; Translational Medical Research

Synaptotagmin is a Ca2+ sensing protein, which triggers a fusion of synaptic vesicles in neuronal transmission. Little is known regarding the expression of Ca2+ - dependent synaptotagmin isoforms and their contribution to the release of secretory vesicles in mouse and rat parotid acinar cells. We investigated a type of Ca2+ - dependent synaptotagmin and Ca2+ signaling in both rat and mouse parotid acinar cells using RT-PCR, microfluorometry, and amylase assay. Mouse parotid acinar cells exhibited much more sensitive amylase release in response to muscarinic stimulation than did rat parotid acinar cells. However, transient [Ca2+]i increases and Ca2+ influx in response to muscarinic stimulation in both cells were identical, suggesting that the expression or activity of the Ca2+ sensing proteins is different. Seven Ca2+ - dependent synaptotagmins, from 1 to 7, were expressed in the mouse parotid acinar cells. However, in the rat parotid acinar cells, only synaptotagmins 1, 3, 4 and 7 were expressed. These results indicate that the expression of Ca2+ - dependent synaptotagmins may contribute to the release of secretory vesicles in parotid acinar cells.
Synaptotagmins/*metabolism ; Signal Transduction ; Rats ; Protein Isoforms/metabolism ; Parotid Gland/cytology/*metabolism ; Muscarinic Agonists/pharmacology ; Mice ; Exocytosis/drug effects/physiology ; Carbachol/pharmacology ; Calcium/metabolism/*physiology ; Animals ; Amylases/secretion

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

Burst firing of dopaminergic neurons in ventral tegmental area (VTA) induces a large transient increase in synaptic dopamine (DA) release and thus is considered the reward-related signal. But the mechanisms of burst generation of dopaminergic neuron still remain unclear. This experiment investigated the burst firing of VTA dopaminergic neurons in rat midbrain slices perfused with carbachol and L-glutamate individually or simultaneously to understand the neurotransmitter mechanism underlying burst generation. The results showed that bath application of carbachol (10 μmol/L) and pulse application of L-glutamate (3 mmol/L) both induced burst firing in dopaminergic neuron. Co-application of carbachol and L-glutamate induced burst firing in VTA dopaminergic cells which couldn't be induced to burst by the two chemicals separately. The result indicates that carbachol and L-glutamate co-regulate burst firing of dopaminergic neuron.
Action Potentials ; drug effects ; Animals ; Carbachol ; pharmacology ; Dopaminergic Neurons ; physiology ; Drug Synergism ; Female ; Glutamic Acid ; pharmacology ; Male ; Rats ; Rats, Sprague-Dawley ; Ventral Tegmental Area ; physiology

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

The present study was aimed to investigate the positive inotropic mechanism of carbachol (CCh) on rat ventricular myocytes. The effects of CCh on L-type calcium current (I(Ca,L)) and Na(+)/Ca(2+) exchange current (I(Na/Ca)) were investigated in isolated rat ventricular myocytes. After loading myocytes with Fura-2/AM, electrically triggered Ca(2+) transient and cell shortening in single myocyte were measured simultaneously using ion imaging system with charge-coupled device (CCD) camera. CCh (100 mumol/L) increased I(Na/Ca) in forward mode from (1.18 +/- 0.57) pA/pF in the control group to (1.65 +/- 0.52) pA/pF (P<0.01) and that in reverse mode from (1.11 +/- 0.49) pA/pF in the control group to (1.53 +/- 0.52) pA/pF (P<0.01), respectively. CCh had no effect on I(Ca,L). The stimulatory effect of CCh on I(Na/Ca) was blocked by application of atropine, a non-selective M muscarinic receptor antagonist, and methoctramine, a selective M(2) muscarinic receptor antagonist. CCh (100 mumol/L) increased cell shortening from (3.00 +/- 0.67) mum in the control group to (3.55 +/- 1.21) mum. Ca(2+) transient was also increased from 203.8 +/- 50.0 in the control group to 234.8 +/- 64.3 in 100 mumol/L CCh group. KB-R7943, a selective inhibitor of reverse mode Na(+)/Ca(2+) exchange, did not change the baseline level of cell shortening and Ca(2+) transient, while completely abolished CCh-induced increments of both Ca(2+) transient and cell shortening. CCh increased cell shortening and Ca(2+) transient in the presence of nicardipine, indicating that the positive inotropic effect of CCh was through activation of Na(+)/Ca(2+) exchange. Calcium sensitivity was not changed by CCh. Both atropine and methoctramine abolished the positive inotropic effects of CCh, demonstrating that CCh induced positive inotropism via the M(2) muscarinic receptor. The results suggest that CCh increases cell contraction and Ca(2+) transient in rat ventricular myocytes. This positive inotropic effect of CCh is through activation of reverse mode Na(+)/Ca(2+) exchange, and M(2) receptors are involved in mediating CCh-induced contraction.
Animals ; Calcium ; Carbachol ; pharmacology ; Heart Ventricles ; Male ; Myocardial Contraction ; Myocytes, Cardiac ; drug effects ; Rats ; Receptor, Muscarinic M2 ; Receptors, Muscarinic ; drug effects ; Sodium ; Sodium-Calcium Exchanger ; Thiourea ; analogs & derivatives

The C-terminus ends of the second putative transmembrane domains of both M-1 and M-2 Muscarinic receptors contain a triplet of amino acid residues consisting of leucine (L), tyrosine (Y) and threonine (T). This triplet is repeated as LYT-TYL in M-1 receptors at the interface between the second transmembrane domain and the first extracellular loop. Interestingly, however, it is repeated in a transposed fashion (LYT-LYT) in the sequence Of M-2 receptors. In our previous work, we investigated the possible significance of this unique sequence diversity for determining the distinct differential receptor function at the two receptor subtypes. However, we found mutation of the LYTTYL sequence of M-1 receptors to the corresponding M-2 receptor LYTLYT sequence demonstrated markedly enhanced the stimulation of phosphoinositide (PI) hydrolysis by carbachol without a change in its coupling to increased cyclic AMP formation. In this work, thus, the enhanced stimulation of PI hydrolysis in the LYTLYT M-1 receptor mutant was further investigated. The stimulation of PI hydrolysis by carbachol was enhanced in the mutant M-1 receptor, and this change was not due to alterations in the rate of receptor desensitization or sequestration. The observed larger response to carbachol at mutant M-1 receptors was also not due to an artifact resulting from selection of CHO cells which express higher levels of G-proteins or phospholipase C. Our data suggest that although the LYTTYL sequence in M-1 muscarinic receptors is not involved in determining receptor pharmacology, mutation of the sequence enhanced the coupling of M-1 receptors to the stimulation of phospholipase C.
Animals ; Artifacts ; Carbachol ; CHO Cells ; Cricetinae ; Cyclic AMP ; GTP-Binding Proteins ; Humans ; Hydrolysis ; Leucine ; Pharmacology ; Phospholipases* ; Receptors, Muscarinic* ; Threonine ; Trinucleotide Repeats* ; Triplets* ; Type C Phospholipases* ; Tyrosine

We investigated the effect of alpha-adrenergic and cholinergic receptor agonists on Ca2+ current in adult rat trigeminal ganglion neurons using whole-cell patch clamp methods. The application of acetylcholine, carbachol, and oxotremorine (50 muM each) produced a rapid and reversible reduction of the Ca2+ current by 17+/-6%, 19+/-3% and 18+/-4%, respectively. Atropine, a muscarinic antagonist, blocked carbachol-induced Ca2+ current inhibition to 3 +/- 1%. Norepinephrine (50 muM) reduced Ca2+ current by 18 +/- 2%, while clonidine (50 muM), an alpha2-adrenergic receptor agonist, inhibited Ca2+ current by only 4 +/- 1%. Yohimbine, an alpha2-adrenergic receptor antagonist, did not block the inhibitory effect of norepinephrine on Ca2+ current, whereas prazosin, an alpha1-adrenergic receptor antagonist, attenuated the inhibitory effect of norepinephrine on Ca2+ current to 6 +/- 1%. This pharmacology contrasts with alpha2-adrenergic receptor modulation of Ca2+ channels in rat sympathetic neurons, which is sensitive to clonidine and blocked by yohimbine. Our data suggest that the modulation of voltage dependent Ca2+ channel by norepinephrine is mediated via an alpha1-adrenergic receptor. Pretreatment with pertussis toxin (250 ng/ml) for 16 h greatly reduced norepinephrine- and carbachol-induced Ca2+ current inhibition from 17 +/- 3% and 18 +/- 3% to 2 +/- 1% and 2 +/- 1%, respectively. These results demonstrate that norepinephrine, through an alpha1-adrenergic receptor, and carbachol, through a muscarinic receptor, inhibit Ca2+ currents in adult rat trigeminal ganglion neurons via pertussis toxin sensitive GTP-binding proteins.
Acetylcholine ; Adult ; Animals ; Atropine ; Carbachol ; Clonidine ; GTP-Binding Proteins ; Humans ; Neurons ; Norepinephrine ; Oxotremorine ; Pertussis Toxin ; Pharmacology ; Prazosin ; Rats ; Receptors, Muscarinic ; Trigeminal Ganglion ; Yohimbine

We isolated mouse embryonic cardiomyocytes derived from timed-pregnant females at different periods and used patch-clamp technique to investigate the muscarinic cholinergic modulation of pacemaker current I(f) in different developmental stages. In early development stage (EDS), muscarinic agonist carbachol (CCh) significantly decreased the magnitude of the pacemaker current I(f) but had no effect in late development stage (LDS). Forskolin (a direct adenylate cyclase activator) and IBMX (a non-selective phosphodiesterase inhibitor) increased I(f) in both EDS and LDS cells. Interestingly, although both forskolin and IBMX increased basal I(f), their effects on CCh-inhibited I(f) were different. Forskolin did not reverse the inhibitory action of CCh until intermediate development stage (IDS). In contrast, IBMX reversed the inhibitory action of CCh on I(f) in EDS but not in IDS. It is suggested that a decrease in intracellular cAMP is a possible mechanism for CCh to modulate I(f). During the EDS and IDS CCh controls the cytoplasmic cAMP level by different pathways: In EDS, CCh modulates I(f) possibly by activating PDE which accelerates the breakdown of cAMP, but in IDS possibly by inhibiting adenylate cyclase (AC) which then reduces the synthesis of cAMP.
Animals ; Carbachol ; pharmacology ; Colforsin ; metabolism ; pharmacology ; Female ; Heart ; embryology ; physiology ; Mice ; Muscarinic Agonists ; pharmacology ; Myocytes, Cardiac ; drug effects ; physiology ; Pacemaker, Artificial ; Phosphodiesterase Inhibitors ; metabolism ; pharmacology ; Pregnancy ; Receptors, Muscarinic ; metabolism