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KMID : 0376219740110041485
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Chonnam Medical Journal
1974 Volume.11 No. 4 p.1485 ~ p.1494
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Studies on the non-adrenergic and non-cholinergic innervation to the rectum in the young and adult chicken
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Abstract
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It has been generally understood that the gastro-intestinal, tracts are under the regulation of antagonistic autonomic innervation most sympathetics exert inhibitory effects through. the mediation of norepinephrine released from the nerve endings and parasympathetics excitatory, effects through acetylcholine.
Recently, however, evidence has been accumulated suggesting that excitatory and inhibitory fibers which are neither adrenergic or cholinergic are innervated to the gastro-intestinal tracts and other organs, and, that a purine nucleotide, probably adenosine triphosphate (ATP), is the neuro-transmitter released from nerves. Accordingly, these nerve fiberss have been tentatively termed purinergic.
In order to study the existence of non-adrenergic and non-cholinergic fibers distributed to the rectum, effects of nerve stimulation and some autonomic drugs were investigated in the rectum-periarterial sympathetics preparation of. the young and adult chicken, The results obtained were as follows:
1. Stimulation of the rectum-periarterial sympathetics preparation from the adult chicken produced only contraction, whereas the stimulation in the young chicken evoked responses in one of the following three patterns: 1) contraction only, 2) contraction followed by relaxation, and 3) relaxation only, the first pattern being the most frequent response in the young chicken.
2. Most effective contractile response was produced by the frequencies ranging from 50 to 60 Hz in the adult chicken, and from 20 to 30 Hz in the young chicken.
3. The contractile response to the periarterial sympathetlc stimulation in both the young and adult chicken was not affected in the presence, of regitine,pro pranolol and atropine
4. The relaxation-response to the periarterial sympathetic stimulation in the young chicken was not affected by the pretreatment with regitine whereas the response was completely abolished in the presence of propranolol
5. Norepinephrine and epinephrine evoked only relaxation inn the isolated rectal muscles of both young and., adult chickenj,-and the relaxation-response was completely abolished in the presence of propranolol.
6. Acetylcholine elicited contraction in, the rectal muscles, of both, young and adult chicken, and the response was completely -blocked. by-the pretreatment with atropine.
7. These results suggest thkt the contractile response in the pdriarterial,sym thetic stimulation in the rectum´ of the young and adult chicken seems to be mediated by the nerve fibers which are neither adrenergic nor cholinergic.
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