5-Hydroxytryptamine receptor antagonism by metoclopramide and ICS 205-930 in the guinea-pig leads to enhancement of contractions of stomach muscle strips induced by electrical field stimulation and facilitation of gastric emptying in-vivo

To investigate the role of prostaglandin (PG) E2 in allergen-induced hyperresponsiveness, dogs inhaled either the allergen Ascaris suum or vehicle (Sham). Twenty-four hours after inhalation, some animals exposed to allergen demonstrated an increased responsiveness to acetylcholine challenge in vivo (Hyp-Resp), whereas others did not (Non-Resp). Strips of tracheal smooth muscle, either epithelium intact or epithelium denuded, were suspended on stimulating electrodes, and a concentration-response curve to carbachol (10−9 to 10−5 M) was generated. Tissues received electrical field stimulation, and organ bath fluid was collected to determine PGE2content. With the epithelium present, all three groups contracted similarly to 10−5 M carbachol, whereas epithelium-denuded tissues from animals that inhaled allergen contracted more than tissues from Sham dogs. In response to electrical field stimulation, Hyp-Resp tissues contracted less than Sham tissues in the presence of epithelium and more than Sham tissues in the absence of epithelium. PGE2release in the muscle bath was greater in Non-Resp tissues than in Sham or Hyp-Resp tissues when the epithelium was present. Removal of the epithelium greatly inhibited PGE2release. We conclude that tracheal smooth muscle is hyperresponsive in vitro after in vivo allergen exposure only when the modulatory effect of the epithelium, largely through PGE2 release, is removed.

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Modulation of calcitonin gene-related peptide release evoked by bradykinin and electrical field stimulation in guinea-pig atria

Neuroscience Letters ◽

10.1016/0304-3940(94)90264-x ◽

1994 ◽

Vol 170 (1) ◽

pp. 163-166 ◽

Cited By ~ 4

Author(s):

Elena Del Bianco ◽

Carlo Alberto Maggi ◽

Paolo Santicioli ◽

Pierangelo Geppetti

Keyword(s):

Guinea Pig ◽

Electrical Field Stimulation ◽

Calcitonin Gene Related Peptide ◽

Field Stimulation ◽

Electrical Field ◽

Related Peptide ◽

Calcitonin Gene ◽

Peptide Release ◽

Guinea Pig Atria

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Effects of mucosal removal on guinea-pig airway smooth muscle responsiveness

Clinical Science ◽

10.1042/cs0700571 ◽

1986 ◽

Vol 70 (6) ◽

pp. 571-575 ◽

Cited By ~ 32

Author(s):

Christopher Murlas

Keyword(s):

Smooth Muscle ◽

Guinea Pig ◽

Airway Smooth Muscle ◽

Contractile Response ◽

Electrical Field Stimulation ◽

Physiological Salt Solution ◽

Induced Responses ◽

Field Stimulation ◽

Electrical Field ◽

Airway Mucosa

1. The contractile response to histamine, acetylcholine (ACh), KCl or electrical field stimulation (EFS) was examined in paired tracheal rings (one of each being denuded by mucosal rubbing), which were mounted in muscle chambers filled with a continuously aerated physiological salt solution at 37°C. 2. Removal of the respiratory mucosa increased the sensitivity of airway muscle to ACh, histamine and EFS, but not to KCl. The hypersensitivity of denuded rings to histamine and EFS was greater than to ACh. Atropine reduced the histamine hypersensitivity observed. 3. Pretreating intact preparations with indomethacin augmented their responsiveness to EFS, histamine and ACh. 4. Indomethacin augmentation of histamine- and EFS-induced responses was greater in preparations without epithelium. 5. We conclude that the airway mucosa may be associated with a factor that reduces airway smooth muscle responsiveness to stimulation.

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