Eylem Seç
Aspects of neuromuscular transmission in the snail Helix pomatia L
Başlık:
Aspects of neuromuscular transmission in the snail Helix pomatia L
Yazar:
Allan, Thomas Lindsay, author.
ISBN:
9780438053632
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (189 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 76-08C.
Advisors: I. A. Boyd.
Özet:
A study has been made of neuro-muscular transmission in the pharyngeal retractor muscle of the pulmonate Gastropod Helix pomatia L, using electro-physiological and other techniques. The average resting membrane potential was - 62 mV and the effect of varying the external K+ concentration was tested. Neural stimulation elicited a graded excitatory junctional potential (EJP) which varied with stimulus strength suggesting polyneuronal innervation. Pontaneous miniature post-synaptic potentials (mpsp's) were detected, their frequency was markedly increased by increasing the osmotic pressure or adding Ba2+, and their discharge was shown to be a random process. In the magnesium-paralysed preparation, the EJP was reduced in size and fluctuated quantally in a manner predicted by the Poisson -function. Neither cholinergic antagonists nor anticholinesterases had any effect on the neurally evoked twitch, however, Acetylcholine (ACh) itself had a complex action, both depolarizing the post- synaptic membrane and blocking transmitter release from the nerve terminals. There was no histchemical evidence of Acetylcholinesterase in the muscle and these results were taken to indicate non-cholinergic transmission. L-Glutamate not only depolarized the muscle but elicited a contraction. The neurally-evoked twitch and the potentials elicited by iontophoretically applied Glutamate were both abolished by a Methyl glutamate. These findings were in keeping with glutaminergic neuro-muscular transmission. The reversal potential for the action of the natural transmitter, by extrapolarization, was +2.0 mV. The lengths and diameters of individual PRM cells were measured on a sonicated preparation and these dimensions were subsequently used in the calculation of membrane constants. The input resistance, Reff, and time constant, Tm, were measured with the aid of a bridge circuit and by making certain assumptions about the length constant, ?, it was possible to estimate the specific membrane resistance and capacitance (Rm and Cm). The results were discussed in relation to other Classes of Mollusca and where appropriate to other Phyla.
Notlar:
School code: 0547
Tüzel Kişi Ek Girişi:
Mevcut:*
Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(684468.1) | 684468-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
On Order
Liste seç
Bunu varsayılan liste yap.
Öğeler başarıyla eklendi
Öğeler eklenirken hata oldu. Lütfen tekrar deneyiniz.
:
Select An Item
Data usage warning: You will receive one text message for each title you selected.
Standard text messaging rates apply.