Facilitation of female reproductive behavior from mesensephalic central gray in the rat

1979 ◽  
Vol 237 (5) ◽  
pp. R278-R284 ◽  
Author(s):  
Y. Sakuma ◽  
D. W. Pfaff
Keyword(s):  
Electrical Stimulation ◽  
Mesencephalic Reticular Formation ◽  
Female Rats ◽  
Motor Systems ◽  
Functional Link ◽  
Implanted Electrodes ◽  
Unilateral Stimulation ◽  
Postural Changes ◽  
Central Gray ◽  
Stimulation Of

Electrical stimulation in the mesencephalic central gray (CG) and adjacent subtectum through chronically implanted electrodes in free-moving estrogen-primed ovariectomized female rats elicited a rapid and large facilitation of the lordosis reflex in response to either male mounts or manula cutaneous stimuli. Unilateral stimulation was sufficient for this effect. The facilitation increased in a graded manner to increased stimulus intensity, and was optimally evoked by stimuli delivered at 50--150 Hz. Facilitation disappeared rapidly following the end ot electrical stimulation, and within 15 min, reflex performance returned to the prestimulation level. Lordosis facilitation appeared when no aversive responses occurred; stimulation with comparable parameters at the lateral edge of CG or in the mesencephalic reticular formation often resulted in postural changes or aversive responses but was not able to facilitate lordosis. Lordosis refelx facilitation was probably mediated by projections descending from neurons in and around the CG, and represents stimulation of a functional link between ascending somatosensory and descending motor systems for the control of lordosis behavior.

Mesencephalic mechanisms for integration of female reproductive behavior in the rat

1979 ◽  
Vol 237 (5) ◽  
pp. R285-R290 ◽  
Author(s):  
Y. Sakuma ◽  
D. W. Pfaff
Keyword(s):  
Electrical Stimulation ◽  
Mesencephalic Reticular Formation ◽  
Female Rats ◽  
Motor Systems ◽  
Cuneiform Nucleus ◽  
Electrolytic Lesions ◽  
The Difference ◽  
Central Gray ◽  
Bilateral Lesions ◽  
Stimulation Of

Placement of bilateral electrolytic lesions in the mesencephalic central gray (CG) of estrogen-primed ovariectomized female rats produced an immediate decline in performance of the lordosis reflex. Lesions that destroyed the dorsal half of the CG and the adjacent subtectal region were effective. The decrease in individual animals in terms of the lordosis reflex score ranged from 20 to 100% of the prelesion performance. Such lesions abolished the facilitation of lordosis by electrical stimulation of the ventromedial nucleus of the hypothalamus. Similar abrupt losses of lordosis followed bilateral lesions of either a) the area between CG and the cuneiform nucleus of the mesencephalic reticular formation (NCf); or b) the ventrolateral quadrant of the NCf. The difference between these two lesions was that the effect of the latter could be overridden by electrical stimulation of the CG, whereas that of the former could not. We conclude that the CG is an important supraspinal component of the circuit for lordosis behavior, constituting a link between ascending somatosensory and descending motor systems for lordosis. It probably facilitates lordosis when activated by behaviorally relevant peripheral somatosensory and/or ventromedial hypothalamic inputs.

Estrogen-sensitive neurons in the female rat ventral tegmental area: a dual route for the hormone action

1993 ◽  
Vol 70 (4) ◽  
pp. 1469-1475 ◽  
Author(s):  
Y. Sakamoto ◽  
S. Suga ◽  
Y. Sakuma
Keyword(s):  
Electrical Stimulation ◽  
Ventral Tegmental Area ◽  
Refractory Period ◽  
Action Potentials ◽  
Female Rats ◽  
Female Rat ◽  
Antidromic Activation ◽  
Ventral Tegmental ◽  
Central Gray ◽  
Stimulation Of

1. Electrical stimulation of the ventral part of the midbrain central gray (CG) elicited antidromic action potentials in 136 neurons in the ventral tegmental area (VTA) of 23 urethan-anesthetized ovariectomized female rats. 2. Antidromic action potentials were positive-negative biphasic and completed mostly within 2.4 ms. Many had a notch in their initial positive deflection, at which antidromic potentials often failed to propagate into the neuronal soma. 3. The latency for antidromic activation ranged 1.0-10.5 ms, and the threshold was 100-1,700 microA. The relative refractory period was 0.8-2.8 ms. In 23 neurons (17%) gradual changes in stimulus intensity caused latency jumps, suggesting that their axons terminate or spread into branches in stimulation sites. 4. The parameters for antidromic activation were compared among 12 animals with a subcutaneous Silastic capsule of estrogen and 11 others with a blank capsule. Estrogen raised the mean threshold from 675 +/- 40 (SE) microA (n = 69) to 908 +/- 40 microA (n = 67). At the same time, estrogen significantly decreased the probability of the antidromic propagation from 63 to 41%. No changes were detected in the latency or the refractory period. 5. The probability distribution of the threshold was different in ovariectomized animals from that in estrogen-treated animals. Estrogen increased the number of cells with thresholds in the 1,300- to 1,500-microA range. 6. The probability of antidromic propagation was stable in each neuron to stimuli repeated at 1.0 Hz. Electrical stimulation of the preoptic area (POA) with a 30-s train of 50-microA pulses at 100 Hz increased the probability of antidromic propagation into the soma.(ABSTRACT TRUNCATED AT 250 WORDS)

ADENOHYPOPHYSEAL LH CONTENT IN NORMAL, ANDROGEN-STERILIZED AND PROGESTERONE-PRIMED STERILE FEMALE RATS

1962 ◽  
Vol 39 (1) ◽  
pp. 13-21 ◽  
Author(s):  
Roger A. Gorski ◽  
Charles A. Barraclough
Keyword(s):  
Ascorbic Acid ◽  
Electrical Stimulation ◽  
Quantitative Determination ◽  
Median Eminence ◽  
Hypothalamic Stimulation ◽  
Female Rats ◽  
Rat Pituitary ◽  
Gland Content ◽  
Stimulation Of

ABSTRACT We have previously suggested that the failure of the androgen-sterilized, persistent-oestrous rat to ovulate, following electrical stimulation of the median eminence structures of the hypothalamus, is due to an insufficiency in adenohypophyseal LH concentration. Using the ovarian ascorbic acid technique for quantitative determination of pituitary LH content, the present studies have demonstrated that the sterile rat pituitary gland contains one-third the LH content of the normal prooestrous gland. Furthermore, not only does progesterone priming of this persistent-oestrous rat result in a 75 % increase in LH concentration, but on hypothalamic stimulation sufficient LH is released to induce ovulation. The decrease in LH concentration which accompanies ovulation in the progesterone-primed, sterile rat is approximately 45 % of the total gland content as compared with a 51 % decrease in pituitary content in the normal cyclic rat.

Plasma 17-hydroxycorticosteroid levels during electrical stimulation of the amygdaloid complex in conscious monkeys

1958 ◽  
Vol 196 (1) ◽  
pp. 44-48 ◽  
Author(s):  
John W. Mason
Keyword(s):  
Electrical Stimulation ◽  
Large Dose ◽  
Rhesus Monkeys ◽  
Hypothalamic Stimulation ◽  
Amygdaloid Complex ◽  
Implanted Electrodes ◽  
Stimulation Of

Substantial plasma 17-OH-CS elevations invariably occurred during electrical stimulation of the amygdaloid complex in unanesthetized rhesus monkeys through chronically implanted electrodes. No evidence of localization of this effect within anatomical subdivisions of the amygdaloid complex was observed. Stimulation of the amygdala elicited plasma 17-OH-CS elevations (20 µg %/hr.) equal to those occurring with hypothalamic stimulation or injection of a large dose of ACTH (16 mg/kg), while no elevations were observed during putamen stimulation or under normal conditions.

SECRETION OF FSH AND LH IN THE PSEUDOPREGNANT RAT

1965 ◽  
Vol 49 (3) ◽  
pp. 370-378 ◽  
Author(s):  
G. P. van Rees ◽  
C. A. de Groot
Keyword(s):  
Electrical Stimulation ◽  
Adult Female ◽  
The Other ◽  
Female Rats ◽  
Cervix Uteri ◽  
Similar Increase ◽  
Clear Cut ◽  
Inhibiting Effect ◽  
Pituitary Glands ◽  
Stimulation Of

ABSTRACT The pituitary LH- and FSH-content was estimated in rats made pseudopregnant by electrical stimulation of the cervix uteri; serum FSH was also estimated. An increase in both FSH- and LH-content was found, which was largest in the pituitary glands collected on the 7th day of pseudopregnancy. A similar increase in pituitary LH-content could be induced in normal adult female rats by a course of injections of 5 mg of progesterone daily. Serum FSH-levels did not show any clear-cut changes during pseudopregnancy, but rose at the end of it. In the discussion a connection is made between the similarity of the result of progesterone treatment and pseudopregnancy on one hand and between the ovulation-inhibiting effect of progesterone and its ability to increase pituitary FSH-and LH-levels on the other.

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