Electrical stimulation of the preoptic area in Eigenmannia : evoked interruptions in the electric organ discharge

2000 ◽  
Vol 186 (1) ◽  
pp. 81-93 ◽  
Author(s):  
C. J. H. Wong
Keyword(s):  
Electrical Stimulation ◽  
Preoptic Area ◽  
Electric Organ Discharge ◽  
Electric Organ ◽  
Stimulation Of

OVULATORY DISCHARGE OF GONADOTROPHINS INDUCED BY HYPOTHALAMIC STIMULATION IN CASTRATED MALE RATS BEARING A TRANSPLANTED OVARY

1966 ◽  
Vol 51 (2) ◽  
pp. 281-289 ◽  
Author(s):  
J. Moll ◽  
G. H. Zeilmaker
Keyword(s):  
Electrical Stimulation ◽  
Preoptic Area ◽  
Hypothalamic Stimulation ◽  
Male Rats ◽  
Corpora Lutea ◽  
Histological Changes ◽  
Experimental Animals ◽  
Cumulus Oophorus ◽  
Dc Current ◽  
Stimulation Of

ABSTRACT Castrated young adult inbred male rats bearing ovarian transplants were subjected to electrical stimulation of the hypothalamus. This was done in order to investigate whether discharge of ovulatory amounts of gonadotrophins could be induced in such male animals by this procedure. Bilateral stimulations with unipolar electrodes and a DC current of 1.5 mA applied during 10 seconds induced in the ovarian grafts histological changes indicating the discharge of ovulatory amounts of gonadotrophins. In animals killed one day after stimulation these changes consisted of displacement of the ova towards the centre of the follicles with loosening of the cumulus oophorus. In one animal the ova had left the follicles. In animals killed three days after stimulation numerous young corpora lutea could be observed. These results were obtained with electrode tips either close to the median eminence, or in the preoptic area. Shamstimulations were ineffective. Some of the experimental animals received progesterone pretreatment. This rendered the stimulations ineffective, if continued until the day preceding stimulation, but seemed without effect on the results of stimulation, if two or three days without progesterone preceded the stimulations.

Mormyromast electroreceptor organs and their afferent fibers in mormyrid fish. II. Intra-axonal recordings show initial stages of central processing

1990 ◽  
Vol 63 (2) ◽  
pp. 303-318 ◽  
Author(s):  
C. C. Bell
Keyword(s):  
Lateral Line ◽  
Electric Organ Discharge ◽  
Electric Organ ◽  
Direct Stimulation ◽  
Postsynaptic Potentials ◽  
Central Processing ◽  
Refractory Periods ◽  
Synaptic Potentials ◽  
Afferent Fibers ◽  
Stimulation Of

1. Physiologically and morphologically identified primary afferent fibers from mormyromast electroreceptor organs were recorded intracellularly. The fiber recordings were made from the nerve root of the posterior lateral line nerve, where the fibers enter the brain, and from the electrosensory lateral line lobe (ELL), near the central terminals of the fibers. 2. The intracellular recordings reveal a variety of potentials, synaptic and nonsynaptic, in addition to the large orthodromic action potentials from the periphery. The goal of the present study was to describe and interpret these various potentials in mormyromast afferent fibers as a first step in understanding the processing of electrosensory information in ELL. 3. Three types of synaptic potentials were recorded inside mormyromast afferent fibers: 1) electric organ corollary discharge (EOCD) excitatory postsynaptic potentials (EPSPs), driven by the motor command that elicits the electric organ discharge (EOD); 2) EPSPs evoked by electrosensory stimulation of electroreceptors in the skin near the electroreceptor from which the recorded fiber originates or by direct stimulation of an electrosensory nerve; and 3) inhibitory postsynaptic potentials (IPSPs) evoked by electrosensory stimulation of more distant electroreceptors. These synaptic potentials can be attributed to synaptic input to postsynaptic cells in ELL that is observed inside the afferent fibers because of electrical synapses between the fibers and the postsynaptic cells. 4. The peripherally evoked EPSPs could frequently be shown to be unitary. The unitary EPSPs were identical to the orthodromic spikes in originating from a single electroreceptor, in threshold, and in latency shift with increasing stimulus intensity. These similarities suggest that the unitary EPSPs are electrotonic EPSPs caused by impulses in other mormyromast afferent fibers that terminate on some of the same postsynaptic cells as the recorded fiber. The peripherally evoked IPSPs had a longer latency than the EPSPs or orthodromic spikes, requiring the presence of an inhibitory interneuron. 5. The peripherally evoked EPSPs, both unitary and nonunitary, show absolute refractory periods of 3-8 ms, followed by relative refractory periods of approximately 8 ms, when tested with two identical stimuli to a nerve. These refractory periods are interpreted as because of refractoriness in the fine preterminal branches of the axonal arbor. 6. A depolarizing afterpotential is commonly associated with the orthodromic spike and probably results from the successful propagation of the spike into the entire terminal arbor. The depolarizing afterpotential has a refractory period that is similar to that of the peripherally evoked EPSPs and that is also interpreted as refractoriness in the fine preterminal branches.(ABSTRACT TRUNCATED AT 400 WORDS)

LESIONS OF THE SUPRACHIASMATIC NUCLEI AND THE SEROTONIN-DEPENDENT PHASIC RELEASE OF LUTEINIZING HORMONE IN THE RAT: EFFECTS ON DRINKING RHYTHMICITY AND ON THE CONSEQUENCES OF PREOPTIC AREA STIMULATION

1980 ◽  
Vol 84 (2) ◽  
pp. 231-236 ◽  
Author(s):  
C. W. COEN ◽  
P. C. B. MacKINNON
Keyword(s):  
Electrical Stimulation ◽  
Luteinizing Hormone ◽  
Preoptic Area ◽  
Ovariectomized Rats ◽  
Suprachiasmatic Nuclei ◽  
Lh Release ◽  
Radiofrequency Lesions ◽  
Pharmacological Manipulations ◽  
Stimulation Of ◽  
Phasic Release

Ovariectomized rats in which <7% of the suprachiasmatic nuclei had been spared by bilateral radiofrequency lesions were distinguishable from those with >40% of the nuclei by their consistent failure to show the oestrogen-induced daily surge of LH, either with or without pharmacological manipulations of serotonin (5-HT), and also by their loss of the normal rhythmicity of drinking. Minor damage to structures adjacent to the suprachiasmatic nuclei was similar in both groups. The identical facility with which electrical stimulation of the preoptic area induced LH release in the two groups of animals suggested that they were not characterized by different degrees of damage to the preopticotuberal pathway. These results are considered in relation to evidence indicating that the suprachiasmatic nuclei represent the densest concentration of 5-HT terminals in the forebrain and also the site of a mechanism involved in the generation of circadian rhythms.

Preoptic Activation of Frog Mating Behavior

Behaviour ◽  
1967 ◽  
Vol 30 (2-3) ◽  
pp. 239-257 ◽  
Author(s):  
Robert S. Schmidt
Keyword(s):  
Electrical Stimulation ◽  
Mating Behavior ◽  
Rana Pipiens ◽  
Preoptic Area ◽  
Preoptic Nucleus ◽  
Bufo Americanus ◽  
Electrode Holder ◽  
Tree Frogs ◽  
Stimulation Of

AbstractThe effects of preoptic lesions on mating calling and mate orientation were studied in Rana pipiens and several species of tree frogs (Hylidae). Mating calling was evoked by electrical stimulation of the preoptic area of Rana pipiens and Bufo americanus. A new chronic electrode holder is described. It is concluded that the region of the dorsal magnocellular preoptic nucleus is needed for mate orientation and that the region of the ventral magnocellular preoptic nucleus is needed for mating calling. It is suggested that these preoptic regions may act mainly as activators of more posterior "centers". Mating calling may have evolved through the origin of connections between pre-existing preoptic activators and a pre-existing release calling "center", rather than through the origin of a new mating calling "center".

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