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Biomedical subjects

M Misawa

Publications and source records attributed to M Misawa.

At least 271 records · Page 15Linked to original sources

Effect of BR-227, a new bromhexine derivative, on secretory activities of tracheal secretory cells.

The effects of BR-227 on secretory activities of canine tracheal secretory cells including behavior of mucus glycoproteins were investigated histologically and histochemically. Following BR-227 treatment at a concentration of alcian blue at pH 2.5 and periodic acid-Schiff (AB (pH 2.5)/PAS) decreased in a concentration-dependent manner. Furthermore, a decrease in the thickness of the acini of submucosal glands and in marked increase in the ratio of acinar inner diameter of the gland to tracheal wall were induced after application of BR-227 at a concentration range of 10(-7) to 10(-4) M. The numbers of goblet and submucosal glandular cells which stained blue and purple with AB (pH 2.5)/PAS were decreased by BR-227 treatment in a concentrations-dependent way, whereas the cells which stained red were markedly increased. In the experiment using a combination of AB at pH 1.0 and PAS, a decrease in sulfated glycoproteins in those secretory cells was observed. Total saccharide and protein concentrations in the incubation fluid increased with BR-227 treatment, while N-acetylhexomsamine concentration tended to decrease. These findings suggest that BR-227 stimulates secretory activities of both goblet cells and submucosal glands, and lowers mucus viscosity in the secretory cells.

Animals↗

A role of lysosomal enzymes in the mechanism of mucolytic action of bromhexine.

The effect of bromhexine on behaviors of lysosomal enzymes in the submucosal gland was investigated using canine tracheal slice preparations, with reference to the histochemical changes in acid glycoproteins (AGP) in the gland. Incubation of tracheal slices with 1% Triton X-100 or 0.0004-0.04% bromhexine for 30 min decreased the number of stained lysosomes in the glandular cells. The decrease in stained lysosomes after treatment with 1% Triton X-100 or 0.04% bromhexine was effectively prevented by addition of 5% lecithin. The number of glandular cells that were stained red (stain index R) in the combined alcian blue at pH 2.5 and periodic acid-Schiff procedure markedly increased by treatment with 1% Triton X-100 or 0.0004-0.04% bromhexine. In the bromhexine treated groups, there was a close correlation (r=0.932, P less than 0.01) between the increase in the number of glandular cells showing the stain index R and the decrease in the number of stained lysosomes in the cells. These findings suggest that the enzymes which are liberated from lysosomes into the cytoplasm by bromhexine may, at least in a part, be involved in the mucolytic action of the agent on AGP contained in mucus granules of the submucosal gland.

Animals↗

Effects of 8-(2-fluoroethyl)-3 alpha-hydroxy-1 alpha H, 5 alpha H-tropaniumbromide benzilate (Ba598Br) on allergy- and drug-induced asthmas.

The effects of Ba598Br, a new atropine derivative possessing a quarternary ammonium salt structure, on the canine airway, including its antiasthmatic effects, were investigated. The in vivo airway resistance was determined using the modified Konzett-Rössler method. Inhalation of 0.01% of Ba598Br had an inhibitory effect against acetyl-choline (ACh, 10 micrograms/kg i.v.)-evoked bronchoconstriction. The effect of Ba598Br was more powerful and longer lasting than that of the same dose of atropine. Pretreatment with Ba598Br (0.3%) and atropine (0.3%) by inhalation produced a remarkable inhibitory effect on the asthmatic bronchoconstriction induced by inhalation of Ascaris suum antigen in naturally sensitized dogs. In this case, Ba598Br showed a potency of approx. twice that of atropine as estimated from the inhibitory percent. On the other hand, in the case of posttreatment (drugs being inhaled after the antigen inhalation), both drugs showed inhibitory effects of equal degree. As for the effects on increased airway secretion at the time of asthmatic attack, both drugs inhibited the excessive secretions without any remarkable change in the viscosity of the secretions. Inhalation of 0.3% Ba598Br showed a powerful antihistamine action with respect to histamine (Hist, 3 micrograms/kg i.v.)-induced bronchoconstriction after the bilateral cervical vagi and superior laryngeal nerves were amputated. However, almost no effect could be observed with the same dose of atropine. Both Ba598Br and atropine showed relaxing actions of the same degree against ACh contraction on the isolated canine trachea, bronchus and bronchiole preparations, with a particularly strong relaxation being observed in the bronchiole. On the other hand, Ba598Br showed relaxing actions against histamine-induced contractions, which were more powerful than those of atropine, in the bronchus and bronchiole. From the above findings, it is suggested that the Ba598Br inhalation brings about antiasthmatic effects by its persistent, powerful anticholinergic actions and its transient but powerful antihistamine actions.

Animals↗

[Difference in the effects of antitussive drugs on respiration and cough reflex].

In order to understand the relationship between the cough and respiratory centers in the brain stem, we investigated the effects of antitussive drugs such as codeine, dextromethorphan, eptazocine and fominoben on respiratory movement and the cough reflex. Coughs were induced using electrical stimulation of the central cut end of the right superior laryngeal nerve in lightly anesthetized dogs. The drugs were administered intraarterially into the vertebral artery. Rate (RR), amplitude (RA) and volume (RV) of the respiration and number (NC) and amplitude (AC) of the cough reflex evoked were measured as indices. Codeine produced a decrease in RR, RV and NC at 0.3 mg and, additionally, AC at 1 mg. Dextromethorphan increased RR and RV and rather enhanced NC and AC at 0.3 mg, but the agent reduced NC and AC at 3 mg even if it increased RR and RV. Eptazocine produced decreases in RA, NC and AC at 1 mg, and, additionally, RV at 10 mg. Fominoben increased RR, RA and RV dose-dependently at 0.3-3 mg, although it depressed NC and AC at 3 mg. These findings suggest that the thresholds for the cough responses and respiratory responses to antitussive drugs are different from drug to drug and that the respiratory centers and cough center in the brain stem are affected in a different manner even qualitatively.

Analgesics↗

[Changes in glycoprotein composition of the tracheal submucosal glands caused by S-carboxymethylcysteine treatment].

The mechanism for the expectorant effect of S-carboxymethylcysteine (S-CMC) was investigated histologically and histochemically using isolated canine trachea. Following S-CMC treatment, the number of total glycoprotein-containing goblet cells (GC) did not change. The numbers of acid glycoprotein (AGP)-, neutral glycoprotein (NGP)-, and sulphated glycoprotein (SGP)-containing GC were also unaltered in a concentration range of 10(-7) to 10(-4) M. On the other hand, the ratio of the acinar inner diameter of submucosal glands (SG) to the tracheal wall thickness significantly increased with 10(-5) and 10(-4) M S-CMC, and the thickness of the acini of SG significantly decreased with 10(-4) M S-CMC. Although the ratio of the numbers of AGP-to NGP-containing glandular cells and AGP content in the cells did not change, the number of SGP-containing glandular cells significantly decreased with 10(-4) M S-CMC, and SGP content in the cells significantly decreased concentration-dependently High concentrations (10(-5) and 10(-4) M) of S-CMC produced increases in total saccharide, protein and N-acetylhexosamine concentrations in the incubation fluid. These findings suggest that S-CMC has a selective secretagogic action on SG, and an action which alters the composition of AGP, a chief viscous factor, in the mucous granules of SG. The expectorant effect of this agent may, at least in part, be ascribable to these actions.

Animals↗

Effects of psychotropics on the periodic fluctuation in EEG synchronized with respiratory rhythms during cough reflex.

It is known that the psychotropics reduce the cough reflex. To clarify the relation between the higher centers and cough reflex, we investigated the psychotropics property of the respiratory periodic fluctuation in EEG during cough reflex and after administration of psychotropics. Male mongrel dogs immobilized were maintained with artificial respiration. The efferent activities of phrenic nerve and scalp EEG were recorded, and on the basis of the resulting observations, crosscorrelation coefficients were computed using a digital computer. The cough reflex was accompanied by an increase in crosscorrelation coefficient (C. C.) between EEG and phrenic nerve activities. the C. C. between EEG and phrenic nerve activities decreased after iv administration of chlorpromazine ( mg/kg), while administration of imipramine (1-3 mg/kg) and diazepam (1-3 mg/kg) increased the C. C., respectively. The increase in the C. C. observed during cough reflex was inhibited by iv administration of these three drugs. The fact that the C. C. increased during cough reflex suggested that the ascending output from respiratory center to the higher center reinforced during this period. Furthermore, it is suggested that the psychotropics inhibited the neuronal mechanisms of the brain stem that plays an important role in cough reflex by acting upon the feedback loop located between the respiratory center and the higher centers.

Animals↗

[Effects of codeine and morphine on the primary humoral immunity of the respiratory tract].

To investigate the effects of centrally acting antitussive drugs, codeine and morphine, on the humoral immunity in the respiratory tract, male guinea pigs were immunized either systemically (i.p.) or locally (intratracheally, i.t.) with sheep red blood cells (SRBC). The development of plaque-forming cells (PFC) was determined using the spleen (S-PFC) and tracheobronchial lymph node cells (T-PFC). (I) Number of S-PFC after i.p. immunization increased to the maximum on day 5. Peak number of S-PFC and T-PFC after i.t. immunization occurred on day 6. (II) i.p. immunization: The drugs were given i.p. for 5 days before or for 4 days after immunization. Morphine (5 mg/kg) given prior to the immunization decreased spleen cellularity. Pretreatments with codeine (15 mg/kg) and morphine (5 mg/kg) also markedly inhibited the number of S-PFC. These drugs given after the immunization hardly affected the number of S-PFC. (III) i.t. immunization: The drugs were given for 5 days before or after the immunization. Codeine (15 mg/kg) given prior to the immunization inhibited the number of S-PFC. Codeine (3, 15 mg/kg) and morphine (1, 5 mg/kg) given before and after the immunization markedly inhibited the number of T-PFC, dose-dependently. These results indicate that codeine and morphine affect the humoral immunity both locally in the respiratory tract and systemically, which cautions against an easygoing use in respiratory diseases.

Animals↗

[Effect of brovanexine on secretory activities of tracheal secretory cells].

The expectorant effect of brovanexine (BvX) was investigated histologically and histochemically using isolated canine trachea. Following BvX treatment, the number of goblet cells (GC) stained positively with the combination procedure of alcian blue at pH 2.5 or pH 1.0 and periodic acid-Schiff was unaffected. The number of GC which stained blue and purple (stain index B & P) was reduced, while the number of GC that stained red (stain index R) was increased. The thickness of the acini of submucosal glands (SG) markedly decreased with 10(-5) and 10(-4)M BvX, and the ratio of the acinar inner diameter to the tracheal wall thickness significantly increased with 10(-4)M BvX. Stain index B & P of glandular cells decreased with 10(-5) and 10(-4)M BvX, which was accompanied by a marked increase in the stain index R. BvX treatment caused increases in total saccharide and protein concentrations in the incubation fluid, while N-acetylhexosamine slightly decreased. Both the BvX-induced histological changes in glandular cells and changes in concentrations of macromolecular components in the incubation fluid were much the same degree as those induced by bromhexine (Bh). The BvX-induced histochemical changes in secretory cells, however, were slighter than those induced by Bh. These findings suggest that BvX is an expectorant possessing both the secretagogic action selectively on SG and a mucolytic action toward acid glycoproteins in granules of secretory cells.

Animals↗

Behavior of mucus glycoproteins of tracheal secretory cells following L-cysteine methyl ester treatment.

The effects of L-cysteine methyl ester on behavior of mucus glycoproteins in canine tracheal secretory cells were investigated histologically and histochemically. Low concentrations (10(-7) and 10(-6)M) of L-cysteine methyl ester produced, as histological changes, decreases in the total goblet cell number and the thickness of the acini of submucosal glands, and an increase in the acinar inner diameter. On the other hand, L-cysteine methyl ester at 10(-5) and 10(-4)M produced an increase in the thickness of the acini and a slight decrease in the acinar inner diameter. Both the total acid glycoprotein and sulphated glycoprotein contents in glandular cells markedly decreased, whereas the neutral glycoprotein content in the cells increased following L-cysteine methyl ester treatment in a concentration-dependent way. Total saccharide and protein concentrations in the incubation fluid increased with 10(-7) and 10(-6)M, but decreased with 10(-5) and 10(-4)M L-cysteine methyl ester. N-Acetylhexosamine concentration in the bathing fluid increased at 10(-7) and 10(-6)M of the agent. These findings suggest that low concentrations of L-cysteine methyl ester stimulate secretory activities of tracheal secretory cells, while at high concentrations the agent stimulates synthesis of mucus glycoproteins in the submucosal glands. Additionally, it is suggested that L-cysteine methyl ester has a marked viscosity lowering effect on the mucus in the secretory cells.

Animals↗

A new screening method for evaluating antitussives in conscious guinea pigs.

In order to evaluate the effects of antitussive agents, a new method for inducing the cough reflex in guinea pigs was devised. Male guinea pigs weighing 300-450 g were fixed in a supine position under non-anesthesia. A puncture electrode made by a stainless steel wire (0.2 mm diameter, 10 cm length) was inserted into the trachea through a guiding cannula (needle size 23G, Terumo). The optimal parameters of electrical stimulation given on the tracheal mucous membrane were a square-wave pulse with a 40 Hz frequency, duration of application 5 s. Fifty percent of antitussive doses (AtD50) of the drugs used in this study were as follows: codeine, 3.35 mg/kg (i.p.), 7.5 mg/kg (p.o.); morphine, 1.2 mg/kg (i.p.), 2.5 mg/kg (p.o.); picoperidamine, 10.9 mg/kg (i.p.), 22.6 mg/kg (p.o.); benproperine, 14.5 mg/kg (i.p.), 22.6 mg/kg (p.o.); fominoben, 13.9 mg/kg (i.p.), 477 mg/kg (p.o.). These AtD50s are much less as compared with those obtained using other methods. These results suggest that the present method for inducing the cough reflex in guinea pigs is useful for the first screening of antitussives, especially when only a small quantity of the materials is available.

Animals↗

Effect of pilocarpine on behavior of mucus glycoproteins of canine tracheal secretory cells.

Behavior of mucus glycoproteins in tracheal secretory cells after treatment with pilocarpine was investigated histologically and histochemically using the isolated canine trachea. Following pilocarpine treatment, the number of total and neutral glycoprotein-containing goblet cells was reduced concentration-dependently. The number of acid glycoprotein (AGP)-containing goblet cells was not altered with 10(-7) and 10(-6) M pilocarpine, but significantly decreased with 10(-5) and 10(-4) M pilocarpine. The thickness of the acini of submucosal glands significantly decreased, and the ratio of acinar inner diameter to tracheal wall thickness increased in 10(-5) and 10(-4) M pilocarpine. AGP content in glandular cells increased in 10(-7) and 10(-6) M pilocarpine, but markedly decreased at concentrations of 10(-5) and 10(-4) M. Pilocarpine treatment caused an increase in N-acetylhexosamine concentration in the incubation fluid. Total saccharide concentration in the incubation fluid decreased in 10(-7) and 10(-6) M pilocarpine, but was not apparently altered at concentrations of 10(-5) and 10(-4) M. These findings suggest that lower concentrations of pilocarpine stimulate synthesis of AGP in goblet and glandular cells much more preferentially than it stimulates discharge of AGP from the cells. While at higher concentrations, the AGP-discharge effect overcomes the stimulation in synthesis.

Animals↗

Analysis of efferent discharges of the phrenic nerve during the cough reflex.

The response of the phrenic nerve activities during the cough reflex was investigated in anesthetized dogs. The phrenic nerve activities were recorded from the central cut end of the nerve. Changes in phrenic nerve activities were evaluated by means of computer analysis using the programs for power spectrum, amplitude histogram, pulse density variation, and autocorrelation. The cough reflex was induced by mechanical stimulation of the tracheal mucosa. The cough reflex evoked was accompanied by an increase in the number of spike potentials and shortening of the respiratory burst period of the phrenic nerve activities. There was a significant correlation between the intensity of expiration and the multiplication product of the mean amplitude of spike potentials and spike numbers of the phrenic nerve activities during the cough reflex. Total activity of the discharge, amplitude of spike potentials, and pulse density of the phrenic nerve activities also increased during the cough reflex, while the autocorrelation coefficient decreased. These changes were inhibited by codeine. The responses of the phrenic nerve activity during the cough reflex were also observed under artificial respiration as well as under spontaneous respiration. These findings indicate that the phrenic nerve activity can be an indicator of the cough reflex, and it is useful for the indicator to investigate the central mechanisms of the cough reflex.

Animals↗

[Effects of antitussive drugs on the central respiratory mechanisms during the cough reflex].

Effects of antitussive drugs on the phrenic nerve activities during the cough reflex were investigated by means of a power spectrum analysis as a quantitative evaluation of each of the frequency band components of the phrenic nerve activities in anesthetized dogs. The efferent activities of the phrenic nerve were recorded from the central cut end of the phrenic nerve. Each fraction of the phrenic nerve activity was fractionated into bands spanning a range of 100 Hz each by a variable filter and analyzed using a program for the power spectrum analysis. The increase in power of each of the frequency band components was observed during the cough reflex induced by mechanical stimulation of the tracheal mucosa. Particularly, the power of the 2 approximately 100 Hz band components increased significantly as compared with the other frequency band components. An i.v. administration of codeine (3 mg/kg) significantly inhibited the increase in power of all frequency band components during the cough reflex. After administration of dextromethorphan (10 mg/kg, i.v.) or fominoben (8 mg/kg, i.v.), the increase in power of the 2 approximately 100 Hz band components of the phrenic nerve activity during the cough reflex was decreased significantly for 5 approximately 10 min; however, the other frequency band components were not affected. These results provide some evidence for a difference between these three antitussive drugs with respect to the mechanisms of action in the process of the central integration for the cough reflex.

Animals↗

[Role of vagus nerves in bronchoconstriction induced by chemical mediators].

The role of the vagal reflex in bronchoconstriction induced by histamine, acetylcholine, serotonin, and PGF2 alpha was investigated in anesthetized dogs using a complete vagal blockade by cooling. We devised a thermode for vagal cooling. The vagal cooling was performed by circulating cold water through the thermode attached to fit snugly around the bilateral cervical vagus nerves. Airway musculature response was measured as a change in ventilation overflow with a modification of the Konzett-Rössler method. Drugs were injected close intraarterially into the right bronchial artery and inhaled into the airway. Afferent impulses of the vagus nerve were abolished by cooling at 0 degree C. When the vagus nerves were cooled to 0 degree C, the ventilation overflow decreased. On the other hand, when the nerves were rewarmed, the ventilation overflow increased again. Bronchoconstriction was produced by close intraarterial injection of histamine, acetylcholine, serotonin, or PGF2 alpha at a dosage of 10 microgram each. The bronchoconstrictions produced by these agents were inhibited by vagal cooling. The bronchoconstrictions induced by histamine, acetylcholine, and serotonin were all 0.00125%, and that by PGF 2 alpha was 0.001%. Inhalations for 10 min were also inhibited by vagal cooling. These findings indicate that the thermode devised in this study is useful for vagal cooling and that vagally mediated bronchoconstriction is a relatively major component of bronchoconstriction induced by chemical mediators.

Acetylcholine↗

[Secretagogue action of glyceryl guaiacolate in tracheal submucosal glands (author's transl)].

The effects of glyceryl guaiacolate on secretory activities of tracheal secretory cells and on behavior of mucus glycoprotein in these cells were investigated histologically and histochemically using isolated canine trachea. Following glyceryl guaiacolate treatment, the number of total glycoprotein-containing goblet cells (GC) did not change. The numbers of acid glycoprotein (AGP)-, neutral glycoprotein (NGP)-, and sulphated glycoprotein (SGP)-containing GC were also unaltered in a concentration range of 10(-7) to 10(-4)M. On the other hand the acinar inner diameter of the submucosal gland (SG) and the acinar inner diameter to wall ratio significantly increased, while thickness of acinus significantly decreased with 10(-6), 10(-5) and 10(-4)M glyceryl guaiacolate. AGP and SGP contents in glandular cells markedly decreased, while the ratio of the numbers of AGP- to NGP-containing glandular cell were the same, suggesting that glyceryl guaiacolate does not change the quality of mucus glycoprotein in GC and SG. Glyceryl guaiacolate produced a marked increase in total saccharide, protein, and N-acetylhexosamine concentrations in the incubation fluid. These findings suggest that glyceryl guaiacolate has no influence on the secretory activity of GC, but markedly stimulates the activity of SG. The secretagogue effect of the agent would be ascribable to stimulation of mucus discharge, but not stimulation of mucus synthesis.

Animals↗

[A quantitative analysis of the phrenic nerve activities during the cough reflex].

The phrenic nerve activity is an appropriate indicator for the output of the respiratory center as a whole, although a quantitative analysis of each of the frequency band components that constitute the neural activities during the respiratory reflex has not yet been made by other investigators. In the present study, we have made a quantitative analysis of each of the frequency band components of phrenic nerve activity during the cough reflex in anesthetized dogs. The efferent activities of the phrenic nerve were recorded from the central cut end of the phrenic nerve. Each fraction of phrenic nerve activity was separated into bands spanning a range of 100 Hz each by a variable filter and analyzed using a program for the power spectrum. The cough reflex was induced by mechanical stimulation of the tracheal mucosa. In the power spectrum analysis of each frequency band, increase in the power of each of the frequency band components was observed during the cough reflex. Particularly, the power of the 2 approximately 100 Hz band components increased significant as compared with the other frequency band components. Such as increase in the power of the 2 approximately 100 Hz band components toward the other frequency band components during the cough reflex was not observed after an i.v. administration of DMPP and lobeline, but the power increased extended over every frequency band. These findings suggest that the process for integrating the cough reflex was different from that of the other respiratory reflexes and that the present method is useful for investigating the central mechanisms of the cough reflex.

Action Potentials↗