Processes of Excitation in the Dendrites and in the Soma of Single Isolated Sensory Nerve Cells of the Lobster and Crayfish (original) (raw)
1955, The Journal of General Physiology
The stretch receptor organs of Alexandrowicz in lobster and crayfish possess sensory neurons which have their cell bodies in the periphery. The cell bodies send dendrites into a fine nearby muscle strand and at the opposite pole they give rise to an axon running to the central nervous system. Mechanisms of excitation between dendrites, cell soma, and axon have been studied in completely isolated receptor structures with the cell components under visual observation. Two sensory neuron types were investigated, those which adapt rapidly to stretch, the fast cells, and those which adapt slowly, the slow cells. 1. Potentials recorded from the cell body of the neurons with intracellular leads gave resting potentials of 70 to 80 mv. and action potentials which in fresh preparations exceeded the resting potentials by about 10 to 20 mv. In some experiments chymotrypsin or trypsin was used to make cell impalement easier. They did not appreciably alter resting or action potentials. 2. It has b...
Sign up to get access to over 50M papers
Sign up for access to the world's latest research
Related papers
General physiology and biophysics, 2002
Action potentials (APs) and impulse responses in the soma and axon of the rapidly and slowly adapting (SA) abdominal stretch receptor neurons of the crayfish (Astacus leptodactylus) were recorded with single microelectrode current-clamp technique. Impulse frequency response to constant current injection was almost constant in the SA neuron while the response decayed completely in the rapidly adapting (RA) neuron. Mean impulse frequency responses to current stimulations were similar in the receptor neuron pairs. In the RA neuron additional current steps evoked additional impulses while a sudden drop in the current amplitude caused adaptation. Impulse duration was dependent on the rate of rise when current ramps were used. Adaptation was facilitated when calculated receptor current was used. Exposing the neuron to 3 mmol/l TEA or scorpion venom resulted in partly elongated impulse responses. SA neuron could continuously convert the current input into impulse frequency irrespective of ...
Structure and function relationship in the abdominal stretch receptor organs of the crayfish
The Journal of Comparative Neurology, 2005
The structure/function relationship in the rapidly and slowly adapting stretch receptor organs of the crayfish (Astacus leptodactylus) was investigated using confocal microscopy and neuronal modeling methods. Both receptor muscles were single muscle fibers with structural properties closely related to the function of the receptors. Dendrites of the rapidly adapting neuron terminated in a common pile of nerve endings going in all directions. Dendrites of the slowly adapting neuron terminated in a characteristic T shape in multiple regions of the receptor muscle. The slowly adapting main dendrite, which was on average 2.1 times longer and 21% thinner than the rapidly adapting main dendrite, induced larger voltage attenuation. The somal surface area of the slowly adapting neuron was on average 51% larger than that of the rapidly adapting neuron. Variation in the neuronal geometry was greatest among the slowly adapting neurons. A computational model of a neuron pair demonstrated that the rapidly and the slowly adapting neurons attenuated the dendritic receptor potential like low-pass filters with cutoff frequencies at 100 and 20 Hz, respectively. Recurrent dendrites were observed mostly in the slowly adapting neurons. Voltage signals were calculated to be propagated 23% faster in the rapidly adapting axon, which is 51% thicker than the slowly adapting axon. The present findings support the idea that the morphology of the rapidly and the slowly adapting neurons evolved to optimally sense the dynamic and the static features of the mechanical stimulus, respectively.
Journal of Neurophysiology, 1998
Purali, Nuhan and Bo Rydqvist. Action potential and sodium current in the slowly and rapidly adapting stretch receptor neurons of the crayfish ( Astacus astacus). J. Neurophysiol. 80: 2121–2132, 1998. Action potentials (APs) and sodium current from the slowly and the rapidly adapting stretch receptor neurons in the crayfish ( Astacus astacus) were recorded with a two microelectrode voltage- and current-clamp technique. In the rapidly adapting neuron the APs had a duration of 3.2 ± 0.2 ms (means ± SE) and an amplitude of 55.2 ± 1.5 mV. In the slowly adapting receptor neuron APs had a duration of 4.1 ± 0.2 ms and an amplitude 79.9 ± 2.0 mV. APs in the rapidly adapting neuron had a larger amplitude if they were recorded from the axon. In the rapidly adapting neuron adaptation of the impulse response was prolonged by hyperpolarization or by exposure to scorpion venom. Also, sinusoidal current stimulation added to the current steps prevented impulse adaptation. Block of the potassium cur...
Pflügers Archiv - European Journal of Physiology, 2011
The effects of antidromic potential spread were investigated in the stretch receptor neurons of the crayfish. Current and potential responses to conductance changes were recorded in the dynamic clamp condition and compared to those obtained by using some conventional clamp methods and a compartmental neuron model. An analogue circuit was used for dynamic calculation of the injected receptor current as a function of the membrane potential and the given conductance change. Alternatively, receptor current responses to a mechanical stimulus were recorded and compared when the cell was voltage clamped to a previously recorded impulse wave form and the resting potential, respectively. Under dynamic clamp, the receptor current had an oscillating waveform which contrasts with the conventional recordings. Frequency, amplitude and sign of the oscillations were dependent on the applied conductance level, reversal potential and electrotonic attenuation. Mean current amplitude and frequency of the evoked impulse responses were smaller under dynamic clamp, especially for large conductance increases. However, firing frequency was larger if plotted against the mean current response. Recorded responses were similar to those calculated in the model. It was not possible to evoke any adaptation in the slowly adapting neuron by using the dynamic clamp. Evoked potential change served as a self limiting response, preventing the depolarization block. However, impulse duration was significantly shorter in the rapidly adapting neuron when the dynamic clamp was used. It was concluded that, in the stretch receptor neurons during a conductance increase, antidromic potential spread modulates the receptor responses and contributes to adaptation.
The Journal of Physiology, 1993
The transducer properties of the rapidly adapting stretch receptor neurone of the crayfish (Pacifastacus leniusculus) were studied using a two-microelectrode voltage clamp technique. 2. The impulse response to ramp-and-hold extensions of the receptor muscle typically consisted of a high frequency burst followed by cessation of impulses within a relatively short time depending on the amplitude of extension. The type of adaptation was consistent with earlier studies. The stimulus-response relationship for the impulse frequency was non-linear and had a slope in a log-log plot of 2-9. 3. When impulse generation was blocked by tetrodotoxin (TTX), (block of Na+ channels) the receptor potential was extension dependent and similar to that found in the slowly adapting receptor. For small extensions there was an initial peak followed by a fall to a steady potential level. For large extensions the potential response during the ramp phase consisted of a peak followed by a constant potential level lasting to the end of the ramp. When the extension changed to the hold phase the potential fell towards a steady state. The relation between extension and amplitude of receptor potential was non-linear and saturated at-40 to-30 mV (extensions > 15% of zero length, lo). 4. When potassium channels were blocked by TEA (50 mM) and 4-aminopyridine (4-AP, 5 mm) (and Na+ channels blocked by TTX) the shape of the generator potential become less complex with an increased amplitude for large extensions. 5. When the receptor neurone was voltage clamped at the resting potential, extension of the receptor muscle produced an inwardly directed receptor current, the stretch-induced current (SIC). The response consisted of a fast transient phase which decayed towards a steady state. The SIC peak amplitude was dependent on extension in a sigmoidal fashion and saturated at 190 nA (extensions > 25 % of lo). The slope of the steepest part of the stimulus-response relation (between 10 and 20 % extension) was 4-7 + 0-25 (mean + s.E.M.) in a log-log plot. 6. The peak amplitude of the SIC increased with increasing extension speed (ramp steepness), the relation between the slope of the ramp and current amplitude being a first order (hyperbolic) function. The amplitude of the receptor current was voltage dependent and had a reversal potential of + 16-2 + 1-8 mV (mean +S.E.M., 32 cells). MS 1767 B. RYDQVIST AND N. PURALI From the reversal potential the permeability ratio, PNa/PK, of the transducer permeability system was calculated to be 1P5. The I-V curve of SIC was non-linear. 7. When the external Ca2+ concentration was lowered the receptor current amplitude increased. This led to displacement of the stimulus-response relation towards smaller extensions. No change in reversal potential was observed. 8. The receptor current amplitude was reduced when the normal bathing solution was replaced by solutions containing mainly Ca2+ or Mg2+ ions. Small changes in the reversal potential for the receptor current were seen. Calculations from the current amplitudes at normal and high divalent cation solutions resulted in the following ratios: Pca/PNa = 0 44 + 0-06 and PMg/PNa = 0-60 + 005 (mean + S.E.M., 4 cells). 9. It is concluded that the transducer properties of the rapidly adapting are similar to the slowly adapting stretch receptor neurone. The permeability ratios of the transducer membrane for different ions,
Biological Cybernetics, 1976
The slowly adapting stretch receptor of the crayfish is inhibited via the large accessory neuron both by reflex activation of this inhibitory interneuron from the stretch receptor itself (autogenic inhibition) and by activation of the interneuron from stretch receptors in other abdominal segments (neighbourinhibition). Neighbour-inhibition increases proportionally with the increase in impulse frequency in the large accessory neuron produced by activity in neighbouring receptors and largely independently of the level of excitation in the stretch receptor itself. A simple model based on intracellular recordings from the receptor neuron predicts this behaviour fairly accurately. In this model each receptor impulse is followed by an IPSP after a delay proportional to the uninhibited interspike interval of the receptor (autogenic inhibition). The other IPSP's arrive randomly distributed in time (neighbour-inhibition). An alternative model in which all IPSP's arrive randomly produces similar results. This latter model can be modified to fit other neuronal systems.
Journal of Comparative Physiology A, 1995
Voltage-dependent variability in the shape of synaptic responses of the LDS interneuron, an identified nonspiking cell of crayfish, to mechanosensory stimulation was studied using intracellular recording and current injection techniques. Stimulation of the sensory root ipsilateral to the interneuron soma evoked a large depolarizing synaptic response. Its peak amplitude was decreased and the time course was shortened when the LDS interneuron was depolarized by current injection. When the cell was hyperpolarized, the peak amplitude was increased and the time course was prolonged. Upon large hyperpolarization, however, the amplitude did not increase further while the time course showed a slight decrease. The dendritic membrane of the LDS interneuron was found to show an outward rectification upon depolarization and an inward rectification upon large hyperpolarization. Current injection experiments at varying membrane potentials revealed that the voltage-dependent changes in the shape of the synaptic response were based on an increase in membrane conductance due to the rectifying properties of the LDS interneuron. Stimulation of the contralateral root evoked a small depolarizing potential comprising an early excitatory response and a later inhibitory component. Its shape also varied depending on the membrane potential in a manner similar to that of the synaptic response evoked ipsilaterally.
Stretch-induced release of proctolin from the dendrites of a lobster sense organ
Reversed-phase high-performance liquid chromatography coupled with a sensitive bioassay was used to quantify the content of proctolin in the peripheral sensory endings of a crustacean mechanoreceptor, the oval organ, and to examine for its release in response to the physiological stimulus of stretch. Material co-eluting with proctolin and showing proctolin-like bioactivity was present in the oval organ and in the nerve trunks containing the 3 sensory axons. Repetitive stretch stimulation, in which the dendrites were exposed to physiological stretch amplitudes, resulted in a significant increase in the release of proctolin from the oval organ in vitro. Approximately 11.7% of the total proctolin stored in the oval organ was released during a 5 min stimulation period. The stretch-evoked release of proctolin was calcium dependent. Since a previous study has shown that proctolin has excitatory effects upon these primary afferents, the present results imply that endogenous proctolin may function to self-modulate the sensory transduction mechanism of these sensory terminals.
Loading Preview
Sorry, preview is currently unavailable. You can download the paper by clicking the button above.