These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Non-adrenergic inhibitory nerves and putative transmitters in the smooth muscle of cat trachea.
    Author: Ito Y, Takeda K.
    Journal: J Physiol; 1982 Sep; 330():497-511. PubMed ID: 7175755.
    Abstract:
    1. Effects of non-adrenergic non-cholinergic inhibitory nerve stimulation on the smooth muscle of the cat trachea were studied in vitro using micro-electrode, double sucrose-gap and tension recording methods.2. Electrical field stimulation with a short pulse (50 mus) evoked an excitatory junction potential (e.j.p.) followed by a twitch, with or without a subsequent small, long-lasting relaxation. This response was abolished by tetrodotoxin (5 x 10(-7) M).3. After pre-treatment with atropine (10(-7) to 5 x 10(-6) M) both e.j.p. and twitch tension were selectively blocked and repetitive stimuli at 20 Hz evoked in some preparations slow membrane hyperpolarization followed by long-lasting relaxation. These effects were abolished by propranolol (2 x 10(-6) M). In the presence of atropine (10(-6) M) and propranolol (2 x 10(-6) M) field stimulation caused no detectable change in tension, membrane potential or membrane resistance.4. 5-Hydroxytryptamine (5-HT) (10(-6) to 5 x 10(-6) M) produced a tonic contracture of the cat trachea. In the presence of atropine, field stimulation induced a marked reduction in the amplitude of the contracture which was only partly suppressed by propranolol (5 x 10(-6) M). During this muscle relaxation, produced by field stimulation in the presence of 5-HT, atropine and propranolol, there was no apparent change in the membrane potential or in membrane resistance. The magnitude of the relaxation was proportional to the number of stimuli applied.5. ATP (< 10(-3) M) and VIP (< 10(-9) M) had no effect on the membrane potential or resistance of the smooth muscle cells of the cat trachea, although higher concentrations of VIP (> 10(-8) M) hyperpolarized the membrane and reduced the membrane resistance. Low concentrations, i.e. ATP 5 x 10(-6) M or VIP 10(-12) M, which had no effects in the electrical membrane properties, caused relaxation of the muscle contracture evoked by 5-HT.6. After desensitization to exogenous ATP or adenosine, in the presence or absence of dipyridamole (2 x 10(-7) M), the amplitude of the muscle relaxation evoked by the activation of non-adrenergic inhibitory nerves was not affected. It was, however, much smaller during partial desensitization to VIP.7. These results indicate that cat tracheal smooth muscles are innervated by non-adrenergic, non-cholinergic inhibitory nerves, which cause muscle relaxation without affecting the electrical membrane properties. The possible involvements of ATP or VIP in the inhibitory nervous transmission is discussed.
    [Abstract] [Full Text] [Related] [New Search]