An electrophysiological study of mechanisms controlling polyp retraction in colonies of the scleractinian coral Goniopora lobata

1976 ◽  
Vol 65 (2) ◽  
pp. 381-393 ◽  
Author(s):  
P. A. Anderson
Keyword(s):  
Electrical Activity ◽  
Mechanical Stimulation ◽  
Scleractinian Coral ◽  
Electrophysiological Study ◽  
Behavioural Response ◽  
Conduction System ◽  
Repetitive Stimulation ◽  
Stimulation Of

1. Electrical or mechanical stimulation of Goniopora lobata produces coordinated retraction of polyps in the colony. With repetitive stimulation, the response spreads in linear, radial increments which become successively smaller with each stimulus. 2. Electrical activity recorded from these colonies is interpreted as originating in a conduction system responsible for effecting the colonial retraction response. The electrical activity spreads incrementally through the colony in a similar manner to the behavioural response. 3. Various hypotheses have been proposed to account for such a spread of electrical acitvity. Of these, only interneural facilitation is of appreciable importance to Goniopora. 4. Temporary termination of a pathway, by the passage of an impulse through it, was found and interpreted as being an additional and important property of the colonial conduction system.

scholarly journals Co-Ordination of Pedal-Disk Detachment in the Sea Anemone Calliactis Parasitica

1969 ◽  
Vol 51 (2) ◽  
pp. 387-396
Author(s):  
I. D. MCFARLANE
Keyword(s):  
Electrical Stimulation ◽  
Electrical Activity ◽  
Mechanical Stimulation ◽  
Average Frequency ◽  
Conduction System ◽  
Identical Stimulus ◽  
Slow Conduction ◽  
Calliactis Parasitica ◽  
Behavioural Sequence ◽  
Stimulation Of

1. Electrical activity has been recorded from the sphincter region of Calliactis parasitica during the behavioural sequence in which the anemone detaches from the substrate and attaches to a Buccinum shell. The ectodermal slow-conduction system (SS1) fires repetitively, the majority of observed pulses occurring in the period prior to detachment (a typical example is 25 SS1pulses at an average frequency of 1 pulse/7 sec.). Shell-tentacle contact is essential for stimulation of SS1activity. 2. Mechanical stimulation of the column excites the SS1, and 30 stimuli at a frequency of about one shock/5 sec. give pedal disk detachment. 3. Electrical stimulation of the ectoderm excites the SS1and about 30 stimuli at frequencies between one shock/3 sec. and one shock/9 sec. produce detachment. Detachment and the SS1 have an identical stimulus threshold. It is concluded that detachment is co-ordinated by the SS1.

Control of shell settling in the swimming sea anemone Stomphia coccinea

1976 ◽  
Vol 64 (2) ◽  
pp. 419-429
Author(s):  
I. D. Lawn
Keyword(s):  
Electrical Stimulation ◽  
Electrical Activity ◽  
Complete Response ◽  
Conduction System ◽  
Sea Anemone ◽  
Interpulse Interval ◽  
Slow Conduction ◽  
Behavioural Sequence ◽  
Pedal Disc ◽  
Stimulation Of

1. Electrical activity has been recorded from Stomphia coccinea during the behavioural sequence in which the detached anemone settles on to a Modiolus shell. 2. When a responsive tentacle contacts the shell, a short, complex burst of pulses is elicited. These remain confined to the region of contact. The endodermal slow-conduction system (SS2) then begins to fire repetitively (a typical example is 16 SS2 pulses at a mean interpulse interval of 5 s) until the pedal disc begins to inflate. Shell-tentacle contact is essential for stimulation of SS2 activity. 3. The complete response, apart from local bending of the column, may be reproduced by electrical stimulation of the SS2 alone. As few as 10 stimuli at frequencies between 1 shock/s and 1 shock/10 s are required to elicit the response.

Neurobiology of the Gorgonian Coelenterates, Muricea Californica And Lophogorgia Chilensis: I. Behavioural Physiology

1979 ◽  
Vol 79 (1) ◽  
pp. 191-204
Author(s):  
RICHARD A. SATTERLIE ◽  
JAMES F. CASE
Keyword(s):  
Mechanical Stimulation ◽  
Liver Extract ◽  
Chemical Stimulation ◽  
Conduction System ◽  
Electrical Impulses ◽  
Additional Stimulation ◽  
Oral Disk ◽  
Stimulation Of ◽  
Conduction Properties ◽  
Stimulus Number

1. Electrical or mechanical stimulation of Muricea californica or Lophogorgia chilensis colonies resulted in withdrawal of polyps in the immediate vicinity of the stimulation point. Additional stimulation did not result in further spread of polyp retraction. 2. Electrical activity was recorded from a colonial conduction system not restricted to the area of polyp withdrawal. Conduction velocity in this conduction system decreased with increasing stimulus number and distance from the stimulation point. 3. Polyp withdrawal in Muricea occurred concomitantly with a burst of facilitating electrical impulses. The withdrawal burst was always preceded by impulses of the colonial conduction system. 4. The pattern of colonial behaviour in gorgonians depends upon the conduction properties of the colonial conduction system, the conduction system(s) of each individual polyp, and the pathways connecting the two. 5. Polyp tentacles bend to the oral disk when presented with liver extract. A burst of electrical impulses was recorded from Muricea polyps during chemical stimulation. These bursts exhibited apparent adaptation and presumably represent muscle potentials resulting from chemoreceptor activation.

An Electrophysiological Study of Parapodial Innervation Patterns in Aplysia Fasciata

1971 ◽  
Vol 55 (2) ◽  
pp. 409-420
Author(s):  
GEORGE M. HUGHES
Keyword(s):  
Electrical Stimulation ◽  
Mechanical Stimulation ◽  
Electrophysiological Study ◽  
General Pattern ◽  
Proprioceptive Feedback ◽  
Innervation Patterns ◽  
Aplysia Fasciata ◽  
Electrophysiological Methods ◽  
Stimulation Of ◽  
Feedback Responses

1. Studies have been made of the patterns of parapodial innervation in Aplysia fasciata and A. depilans using electrophysiological methods. 2. Sensory fibres are chiefly found in the main parapodial nerves. The areas innervated by these nerves overlap somewhat and such overlapping extends to the branches of individual parapodial nerves. 3. Responses to mechanical stimulation of the parapodial surface gives rise to varying sizes of spike, the smaller spikes being usually more slowly adapting, the larger being highly phasic. 4. Although the general pattern of innervation is common to all specimens there are wide variations in detail. 5. Electrical stimulation of parapodial nerves produces mechanical contractions which are associated with responses in some of the sensory fibres. Usually the afferent units which are stimulated in this way have sensory fields within overlapping areas supplied by the two branches. Such proprioceptive feedback responses usually declined with repetition.

scholarly journals Nerve Nets and Conducting Systems in Sea Anemones: Two Pathways Excite Tentacle Contractions in Calliactis Parasitica

1984 ◽  
Vol 108 (1) ◽  
pp. 137-149
Author(s):  
IAN D. MCFARLANE
Keyword(s):  
Electrical Activity ◽  
Conduction System ◽  
Sea Anemones ◽  
Single Shock ◽  
Nerve Net ◽  
Slow Conduction ◽  
Calliactis Parasitica ◽  
Slight Movement ◽  
Pulse Stimulation ◽  
Stimulation Of

1. Single shocks to the column sometimes evoke tentacle contractions, ranging from slight movement of a few scattered tentacles to rapid bending or shortening of all the tentacles. Some individuals are more responsive than others. Complex bursts of electrical activity follow single shocks, but only in tentacles that contract. 2. These single shocks excite pulses in two conducting systems - the through-conducting nerve net (TCNN) and the ectodermal slow conduction system (SSI). When a single shock evokes contractions and bursts of electrical activity, these usually follow the SSI pulse, rarely the TCNN pulse. Stimulation of the SSI alone causes tentacle contraction in responsive anemones. 3. Fast tentacle contractions always follow the second of two closelyspaced TCNN pulses: the TCNN shows facilitation (Pantin, 1935a). An SSI pulse, however, does not facilitate subsequent pulses in either the SSI or TCNN. 4. There are two pathways for activation of tentacle contractions. The TCNN pathway is mechano-sensitive and normally requires facilitation. The SSI pathway is mechano- and chemosensitive, only requires a single SSI pulse to evoke contraction, but is very labile. It is proposed that the TCNN and the SSI do not excite the ectodermal muscles directly, but via a multipolar nerve net.

Two Slow Conduction Systems in the Sea Anemone Calliactis Parasitica

1969 ◽  
Vol 51 (2) ◽  
pp. 377-385 ◽  
Author(s):  
I. D. MCFARLANE
Keyword(s):  
Electrical Activity ◽  
Conduction Velocity ◽  
Conduction System ◽  
Repetitive Stimulation ◽  
Sea Anemone ◽  
Response Delay ◽  
The Third ◽  
Slow Conduction ◽  
Calliactis Parasitica ◽  
Oral Disk

1. Suction electrodes record electrical activity associated with three conduction systems in the sea anemone Calliactis parasitica. The two slow systems (SS1 and SS2) are previously undescribed. The third system is the through-conduction system. 2. Evidence is given that the SS1 and SS2 are located in the ectoderm and endoderm respectively. The conductile elements have not been identified. 3. The conduction velocity of the SS1 is 4.4-14.6 cm./sec. at 11° C. and is highest in the oral disk. The SS2 velocity is 3.0-5.3 cm./sec. 4. Both slow systems show a marked increase in response delay on repetitive stimulation and fail at stimulation frequencies higher than one shock/3 sec.

Localized Changes in Electrical Activity of the Hypothalamus in Estrous Cats Following Vaginal Stimulation

1957 ◽  
Vol 189 (1) ◽  
pp. 145-151 ◽  
Author(s):  
Robert W. Porter ◽  
Edward B. Cavanaugh ◽  
B. Vaughn Critchlow ◽  
Charles H. Sawyer
Keyword(s):  
Electrical Activity ◽  
Mechanical Stimulation ◽  
Lateral Hypothalamus ◽  
Medial Forebrain Bundle ◽  
Nervous Activity ◽  
High Amplitude ◽  
Eeg Changes ◽  
Eeg Pattern ◽  
Stimulation Of ◽  
Vaginal Stimulation

In experiments designed to record central nervous electrical activity related to neurogenic stimulation of the adenohypophysis, hypothalamic EEG records were made of the effects of vaginal stimulation in the estrous cat. Mechanical stimulation, known to be capable of activating release of pituitary ovulating hormone in the estrous animal, evoked a reproducible EEG pattern in the anterior and lateral hypothalamus, in and around the medial forebrain bundle. This alteration of the spontaneous resting EEG was characterized by bursts of increased frequency and amplitude lasting several seconds or by trains of high amplitude slow waves. These changes recurred spasmodically for 3–7 minutes and may be temporally related to the behavioral after-reaction in the unrestrained unanesthetized cat. Although present in 10 out of 13 estrous cats no such EEG changes could be recorded in any of 9 anestrous animals. The likelihood that these alterations in nervous activity represent some of the electrical concomitants of neurogenic stimulation of the release of pituitary ovulatory hormone is discussed.

Mechanical stimulation of human BON cells: Gαq involvement in 5-HT release

2001 ◽  
Vol 120 (5) ◽  
pp. A83-A83
Author(s):  
M KIM ◽  
N JAVED ◽  
F CHRISTOFI ◽  
H COOKE
Keyword(s):  
Mechanical Stimulation ◽  
Bon Cells ◽  
Stimulation Of
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