scholarly journals Influence of extracellular pH on biphasic contractile response of guinea pig vas deferens to electrical field stimulation

1998 ◽  
Vol 76 ◽  
pp. 303
Author(s):  
Hironori Nakanishi ◽  
Isao Matsuoka ◽  
Tomoyuki Ono ◽  
Junko Kimura
Keyword(s):  
Guinea Pig ◽  
Vas Deferens ◽  
Contractile Response ◽  
Electrical Field Stimulation ◽  
Extracellular Ph ◽  
Field Stimulation ◽  
Electrical Field

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

1986 ◽  
Vol 70 (6) ◽  
pp. 571-575 ◽  
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.

Cholinergic and nonadrenergic mechanisms in human and guinea pig airways

1984 ◽  
Vol 56 (4) ◽  
pp. 958-965 ◽  
Author(s):  
S. M. Taylor ◽  
P. D. Pare ◽  
R. R. Schellenberg
Keyword(s):  
Guinea Pig ◽  
Contractile Response ◽  
Electrical Field Stimulation ◽  
Field Stimulation ◽  
Inhibitory Pathway ◽  
Electrical Field ◽  
Methods Of Analysis ◽  
Human Airways ◽  
Human Bronchi

Electrical field stimulation (70 V, 1 ms, 0.2–500 Hz) of human bronchial strips and guinea pig tracheal chains produced contractile and relaxant responses. Contractions were blocked by atropine, 10(-6) M, and tetrodotoxin (TTX), 0.1–1.0 micrograms/ml, demonstrating a cholinergic excitatory neural component. Frequencies causing half-maximal contractile response to field stimulation (EFc 50) were 10 +/- 2 Hz for guinea pig and 13 +/- 1 Hz for human airways. Relaxations were unmasked by atropine 10(-6) M and slightly diminished by propranolol in guinea pig but not human airways, demonstrating a predominantly nonadrenergic inhibitory pathway in both species. Relaxation of intrinsic tone occurred at stimulation frequencies of 1 Hz or more. Frequencies causing half-maximal relaxation (EFi 50) were 3.5 +/- 0.3 Hz for guinea pig trachealis and 38 +/- 6 Hz for human bronchi. Following 1 microgram/ml TTX, EFi 50 values increased to 104 +/- 12 and 70 +/- 14 Hz, respectively. Frequencies of field stimulation that were inhibitable by TTX (less than or equal to 20 Hz) induced greater relaxation in guinea pig than human airways (70 vs. 10% of the maximal relaxation to 10(-2) M theophylline, respectively). The methods of analysis outlined in this study can be used to compare relative degrees of functional innervation between tissues from the same or different species.

Tetrodotoxin-resistant release of ATP from guinea-pig taenia coli and vas deferens during electrical field stimulation in the presence of luciferin-luciferase

1981 ◽  
Vol 59 (10) ◽  
pp. 1094-1100 ◽  
Author(s):  
Thomas White ◽  
Pamela Potter ◽  
Catherine Moody ◽  
Geoffrey Burnstock
Keyword(s):  
Guinea Pig ◽  
Action Potentials ◽  
Vas Deferens ◽  
Contractile Response ◽  
Atp Release ◽  
Electrical Field Stimulation ◽  
Field Stimulation ◽  
Taenia Coli ◽  
Initial Exposure ◽  
Low Tone

Guinea-pig taenia coli was superfused with medium containing luciferin-luciferase at 25 °C in order to directly detect the release of ATP. The resting lone of the tissue increased during the first 2–10 min of superfusion and then fell to a low level where spontaneous activity ceased. Under high tone conditions during the first 2–10 min of exposure to luciferin-luciferase, in the presence of atropine and guanethidine, ATP was released and the taenia coli relaxed when stimulated at 2–4 Hz, 70 V, 0.3-ms pulses for 15 s. Variable and continuous changes of tone made it difficult to test whether relaxation and release of ATP were tetrodotoxin sensitive. Field stimulation of preparations showing low tone after the initial exposure to luciferin-luciferase also resulted in ATP release. The muscle usually contracted during stimulation, even in the presence of atropine. Release was not due to movement of the muscle, since the release preceded the movement of the tissue and contraction with acetylcholine failed to release ATP. Neither release nor the contractile response of the tissue were blocked by tetrodotoxin (3 × 10−6 M), suggesting that under these conditions the release of ATP originated from the muscle or possibly directly from nerve terminals. A qualitatively similar release of ATP was also observed when desheathed guinea-pig vas deferens was field-stimulated electrically in the presence of luciferin-luciferase. Tetrodotoxin did not block ATP from this tissue either, but unlike the taenia coli, it did abolish the contractile response, which was not affected by luciferin-luciferase during the 1st h of exposure. It is concluded that in the presence of luciferin-luciferase the field-stimulation induced release of ATP observed in guinea pig taenia coli or vas deferens was not mediated by propagation of action potentials in nerve.

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