Release and depletion of the transmitter in adrenergic terminals produced by nerve impulses after the inhibition of noradrenaline synthesis or reabsorption

The nervous system remains one of the least understood biological structures due in large part to the enormous complexity of this organ. A theoretical model for the transfer of nerve impulses would be valuable for the analysis of various phenomena in the nervous system, which are difficult to study by experiments. The central nervous system is composed of more than 100 billion neurons, through which information is transmitted via nerve impulses. Nerve impulses are not immediately apparent since each impulse may be blocked during transmission, changed from a single impulse into repetitive impulse, or integrated with impulses from other neurons to form highly intricate patterns. In the human central nervous system, a neuron secretes a chemical substance called a neurotransmitter at the synapse, and this transmitter in turn acts on another neuron to cause excitation, inhibition, or some other modification of its sensitivity.

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Inhibition of noradrenaline synthesis and the pressor response to tyramine

Journal of Pharmacy and Pharmacology ◽

10.1111/j.2042-7158.1965.tb07657.x ◽

1965 ◽

Vol 17 (4) ◽

pp. 248-249 ◽

Cited By ~ 1

Author(s):

B. Bhagat ◽

Kin Shein

Keyword(s):

Pressor Response ◽

Noradrenaline Synthesis

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The initiation of nerve impulses by mesenteric Pacinian corpuscles

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1950.0026 ◽

1950 ◽

Vol 137 (886) ◽

pp. 96-114 ◽

Cited By ~ 23

Keyword(s):

Conditioning Stimulus ◽

Mechanical Stimulus ◽

Constant Current ◽

Mechanical Stimuli ◽

Pacinian Corpuscles ◽

Nerve Impulses ◽

A Value ◽

Test Shock ◽

Long Duration ◽

Refractory State

A preparation of a single Pacinian corpuscle in the cat’s mesentery has been used to study the initiation of nerve impulses in sensory endings. The minimum movement of a mechanical stimulator required to excite a single corpuscle has been found to be 0⋅5 μ in 100 μ sec. It has been difficult to produce repetitive discharges with rectangular pulses of long duration, either mechanical or of constant current. The latency between a mechanical stimulus and the initiation of an impulse has a value around 1⋅5 msec, for threshold stimuli, and this decreases to a minimum value around 0⋅5 msec, as the stimulus is increased; it is altered only slightly, if at all, by changes in the duration of the maintained displacement of the mechanical stimulator. Subthreshold mechanical stimuli have been shown to facilitate stimulation by electrical test shocks. The return of excitability at the ending is independent of the nature of the conditioning stimulus and varies but little with the nature of the test shock. The value of the latency at threshold is unaffected by the relatively refractory state. The relations of these results to various hypotheses are discussed, and it is suggested that these results can all be accounted for in terms of the known properties of axons.

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Rapid Contractions and Associated Potentials in a Sand-Dwelling Anemone

Journal of Experimental Biology ◽

10.1242/jeb.51.2.513 ◽

1969 ◽

Vol 51 (2) ◽

pp. 513-528

Author(s):

PETER E. PICKENS

Keyword(s):

Maximum Size ◽

Mechanical Stimulus ◽

Retractor Muscle ◽

Mechanical Stimuli ◽

Nerve Impulses ◽

Electrical Potentials ◽

Spread Of Excitation ◽

Electrical Stimuli ◽

Withdrawal Response ◽

Muscle Potential

1. Two kinds of electrical potentials can be recorded from the surface of the. retractor muscle of the anemone, Calamactis, during rapid contraction. These are large muscle action potentials and smaller pulses which are thought to be nerve spikes The latter resemble nerve impulses of higher organisms in that they are all-or-none and of short duration. 2. A nerve spike follows each of a pair of electrical stimuli, but the muscle potential and contraction occur only after the second shock, indicating that facilitation is required at the neuromuscular junction. 3. The size of the muscle potential and of the contraction are correlated with the interval between paired electrical stimuli. Maximum size is reached when stimuli are zoo msec. apart even though the minimum effective interval is 30 msec. 4. A muscle potential precedes contraction only along the upper part of the retractor muscle and this is the part that contracts rapidly during the withdrawal response. The lower retractor does not contract. 5. Conduction velocity along the upper retractor is higher than along the lower. The histological correlate of rapid conduction is a nerve net with large, long, longitudinally oriented fibres. 6. The refractory period of the conducting system of the upper retractor is shorter than that of the lower retractor. Consequently, spread of excitation toward the aboral end is limited if paired stimuli are further apart than 250-300 msec. 7. A mechanical stimulus which is just strong enough to elicit a withdrawal response evokes a single muscle potential of maximum size, suggesting that two nerve impulses closer together than 200 msec. precede the muscle potential. Stronger mechanical stimuli evoke a burst of muscle potentials.

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