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Studies on the innervation of the small and large intestine of the rabbit
Başlık:
Studies on the innervation of the small and large intestine of the rabbit
Yazar:
Lawson, William Ronald, author.
ISBN:
9780438054882
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (275 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 76-08C.
Advisors: Beverly R. MacKenna.
Özet:
This thesis describes in vitro investigations into the autonomic innervations of the rabbit intestine. The innervated rabbit colon preparation described by Garry & Gillespie (1955) and lengths of innervated lleum wore used for these studies. The thesis comprises an investigation into the effects of two adrenergic beta receptor blooking agents (pronethalol and propranolol) and one adrenergic alpha receptor blocking agent (phenoxybenzamine) on the response of the intestine both to nerve stimulation and to added catecholamines. It appears from these investigations that the response to sympathetic nerve stimulation is mediated via beta receptors only whereas the response to catecholamines is mediated via both alpha and beta receptors. This investigation is in Part I of the thesis. The alpha receptor blocking agent phenoxybenzamine potentiates the response to sympathetic nerve stimulation. It was suggested by Burn & Gibbons (1964) that this potentiation was due to the anticholinesterase action of phenoxybenzamine at a proposed cholinergic link on the post-ganglionic sympathetic nerve pathway. The effects of the adrenergic beta receptor blocking agents promethalol and propranolol and the adrenergic alpha receptor blocking agent phenoxy-benzamine were examined on the spontaneous activity of the rabbit intestine and on its responses to catecholamines and to sympathetic and parasympathetic nerve stimulation. 2. All three drugs reduced the spontaneous activity of the intestine and this effect was most noticeable with pronethalol. 3. Pronethalol and propranolol reduced the responses to added catecholamines in the order IP>A>NA indicating p receptor blockade. Phenoxybenzamine potentiated responses to IP and occasionally also to A and NA. 4. Pronethalol and propranolol both reduced the response of the intestine to sympathetic norve stimulation. They could also reduce the response to parasympathetic nerve stimulation. Pronothalol was more specific than propranolol in blocking the sympathetic nerves. Reduction of the response to parasympathetic nerve stimulation. Pronethalol was more specific than propranolol in blocking the sympathetic nerves. Reduction of the parasympathetic response by propranolol was probably due to its local anaesthetic action, but in the case of pronethalol antagonism of acetylcholine and general depression of smooth muscle contractility also played a part. 5. Phenoxybenzamine protentiated the response of the intestine to sympathetic nerve stimulation and reduced the response to parasympathetic nerve stimulation. 6. Experiments using combinations of alpha and beta blocking agents confirm that both alpha and beta Receptors are involved in the response of the intestine to added catecholamines. They have also led to the suggestion that the response of the intestine to sympathetic nerve stimulation is mediated via ? receptors alone.
Notlar:
School code: 0547
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(684507.1) | 684507-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
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