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.

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.

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.

scholarly journals Submicroscopic Changes of the Nerve Endings in the Adrenal Medulla after Stimulation of the Splanchnic Nerve

1957 ◽  
Vol 3 (4) ◽  
pp. 611-614 ◽  
Author(s):  
Eduardo De Robertis ◽  
Alberto Vaz Ferreira
Keyword(s):  
Electrical Stimulation ◽  
Electron Microscope ◽  
Adrenal Medulla ◽  
Synaptic Vesicles ◽  
Splanchnic Nerve ◽  
The Other ◽  
Nerve Endings ◽  
The Mean ◽  
Increased Activity ◽  
Stimulation Of

The nerve endings of the adrenal medulla of the rabbit were studied under the electron microscope in the normal condition and after prolonged electrical stimulation of the splanchnic nerve. With a stimulus of 100 pulses per second for 10 minutes, there is an increase in the number of synaptic vesicles in the nerve ending. The mean number is of 82.6 vesicles per square micron in the normal and of 132.7 per square micron in the stimulated glands. With a stimulus of 400 pulses per second for 10 minutes, there is a considerable depletion of synaptic vesicles and other changes occur in the nerve endings. The mean number of vesicles is of 29.2 per square micron. These results are interpreted as indicative of an increased activity of the ending in one case, and as a diminished activity and fatigue of the synaptic junction in the other.

COMPARISON OF FOLLICLE-STIMULATING HORMONE AND LUTEINIZING HORMONE SECRETION AFTER ELECTRICAL STIMULATION OF THE PREOPTIC PART OF THE HYPOTHALAMUS IN FEMALE RATS ANAESTHETIZED WITH ETHYL CARBAMATE OR SODIUM PENTOBARBITONE

1978 ◽  
Vol 78 (1) ◽  
pp. 151-152 ◽  
Author(s):  
R. G. DYER ◽  
M. B. TER HAAR ◽  
LINDA C. MAYES
Keyword(s):  
Electrical Stimulation ◽  
Luteinizing Hormone ◽  
Follicle Stimulating Hormone ◽  
Hormone Secretion ◽  
Control Process ◽  
Female Rats ◽  
Female Rat ◽  
Luteinizing Hormone Secretion ◽  
Stimulation Of ◽  
Stimulating Hormone

A.R.C. Institute of Animal Physiology, Babraham, Cambridge, CB2 4AT (Received 17 January 1978) For over 30 years, the method by which the brain regulates the secretion of gonadotrophic hormones has been studied by electrical stimulation of those parts of the central nervous system thought to be implicated in the control process. Much of the work has been performed on the female rat. In this species, anaesthetic doses of sodium pentobarbitone, administered immediately before the pro-oestrous 'critical period', block the preovulatory surge of luteinizing hormone (LH) for 24 h. The same treatment also reduces the early phase of the pro-oestrous secretion of follicle-stimulating hormone (FSH; Daane & Parlow, 1971). Electrical stimulation of the preoptic part of the hypothalamus can overcome this blocking effect and analysis of the optimum parameters required to restore normal secretion of gonadotrophins may give some insight into the endogenous process (e.g. Everett, 1965; Fink & Aiyer, 1974;

STEROIDALINTERACTIONS IN THE REGULATION OF MATERNAL BEHAVIOUR IN VIRGIN FEMALE RATS: EFFECTS OF TESTOSTERONE, DIHYDROTESTOSTERONE, OESTRADIOL, PROGESTERONE AND THE AROMATASE INHIBITOR, 1,4,6-ANDROSTATRIENE-3,17-DIONE

1981 ◽  
Vol 90 (1) ◽  
pp. 31-40 ◽  
Author(s):  
R. S. BRIDGES ◽  
D. W. RUSSELL
Keyword(s):  
Aromatase Inhibitor ◽  
Virgin Female ◽  
Rapid Onset ◽  
The Other ◽  
Female Rats ◽  
Maternal Responsiveness ◽  
Maternal Behaviour ◽  
Final Study ◽  
The Mean ◽  
Stimulation Of

The effects of exposure to concentrations of androgens, oestradiol (OE2) and progesterone similar to those found during pregnancy on the induction of maternal behaviour were investigated in female rats. In the first experiment the effects of testosterone and dihydrotestosterone (DHT) administered in combination with progesterone (using silicone elastomer capsules) on the induction of behavioural responsiveness towards young (crouching, retrieval and grouping of pups) were measured in ovariectomized virgin rats. Hormonally treated animals were exposed to testosterone or DHT from day 1 of treatment to the end of behavioural testing, while progesterone was administered for 10 days (days 3–13). Testing for maternal responsiveness began on day 14 and lasted until day 23. Significant reductions in latencies to show individual aspects of and complete maternal behaviour were found only in animals treated with a combination of testosterone and progesterone (range of mean latencies for showing one aspect of, to complete, maternal behaviour = 1·0–1·4 days). The mean latencies of the other hormonally treated animals ranged from 5 to 6 days and were similar to those of non-hormonally treated control rats. The second experiment examined the possibility that stimulation of maternal behaviour in animals given testosterone and progesterone resulted from the aromatization of testosterone to OE2. Ovariectomized virgin rats were implanted with capsules containing testosterone and others with the aromatase inhibitor, 1,4,6-androstatriene-3,17-dione (ATD) on day 1, and with progesterone capsules on day 3. Progesterone capsules were removed on day 13 and behavioural testing commenced on day 14. Treatment with testosterone and progesterone failed to stimulate maternal behaviour in rats treated with ATD. In a third study ovariectomized virgin rats were implanted with OE2 on day 1 and progesterone on day 3. The progesterone implants were removed on day 13 and testing began on day 14. Significant reductions in latencies to show all aspects of maternal behaviour were found in these rats. In a final study progesterone capsules remained in OE2- and progesterone-treated rats from day 3 until the completion of behavioural testing. The presence of progesterone implants throughout the test period (days 14–23) blocked the rapid onset of maternal responsiveness induced by removal of progesterone on day 13 shown in rats treated with OE2 plus progesterone in experiment 3. These data suggest that during gestation testosterone, through its conversion to OE2, synergizes with progesterone to help stimulate the development of the capacity of the female animal to respond maternally to young, a capacity unmasked by withdrawal of progesterone before parturition.

Modification in activity of medullary respiratory-related neurons for vocalization and swallowing

1994 ◽  
Vol 71 (6) ◽  
pp. 2294-2304 ◽  
Author(s):  
C. R. Larson ◽  
Y. Yajima ◽  
P. Ko
Keyword(s):  
Electrical Stimulation ◽  
Vocal Fold ◽  
Discharge Rate ◽  
The Other ◽  
Nucleus Ambiguus ◽  
Macaca Nemestrina ◽  
Deep Inspiration ◽  
Subglottal Pressure ◽  
Posterior Cricoarytenoid ◽  
Stimulation Of

1. The medullary ventral respiratory group (VRG) in and near the nucleus ambiguus contains neurons related to respiration. Also found here are neurons related to vocalization and swallowing as well as motoneurons of laryngeal, pharyngeal, palatal, and esophageal muscles. Previous reports in anesthetized animals have characterized discharge properties of neurons as they relate to a single behavior, e.g., respiration. Relatively few studies have documented discharge properties during more than one behavior, e.g., respiration and swallowing. Neurons were recorded extracellularly from awake Macaca nemestrina monkeys engaged in a vocalization task. The present paper describes how respiratory-related neurons (RRNs) modify their discharge during vocalization and swallowing. 2. The temporal relation between vocalization, subglottal pressure (SP), and diaphragm electromyogram (EMG) was established from recordings in anesthetized monkeys. Vocalization was elicited by electrical stimulation of the midbrain periaqueductal gray (PAG). Vocalization is preceded by deep inspiration and a brief pause in diaphragm EMG and begins with a rapid increase in positive SP. 3. Extracellularly recorded neural potential from the VRG in three awake monkeys were related to respiration by correlating their discharge with EMGs from the posterior cricoarytenoid or intercostal muscles during quiet respiration. Neurons were classified as inspiratory (INSP; N = 27), phase spanning (PS; N = 20), or expiratory (N = 6) on this basis. 4. A fourth category of cells was defined as a subgroup of INSP cells on the basis of their discharge during vocalization. This group, inspiratory-pause (INSP-PS; N = 10), paused for approximately 100 ms just before vocalization and resumed their activity during vocalization. 5. Of 63 fully analyzed RRNs, 40 (63%) also modulated their activity with vocalization and 3 (5%) with swallowing. Thirteen (21%) RRNs modulated with vocalization, respiration, and swallowing. Seven (11%) cells were modulated only with respiration. 6. Most cells demonstrated a shorter period of activity and a higher discharge rate associated with vocalization in comparison with quiet respiration. Six (30%) of the PS cells demonstrated an augmenting discharge pattern before vocalization, which was different from the other PS cells and different from their pattern during quiet respiration. Thirteen RRNs showed a pause in activity during vocal fold closure associated with swallowing, whereas three cells gave a burst at this time. 7. The higher discharge rate and shorter burst duration preceding vocalization, compared with quiet respiration, may be related to the greater positive SP necessary to support vocalization.(ABSTRACT TRUNCATED AT 400 WORDS)

EFFECTS OF NEONATAL EXPOSURE TO MONOSODIUM GLUTAMATE ON THE ELECTRICAL ACTIVITY OF NEURONES IN THE MEDIOBASAL HYPOTHALAMUS, AND ON THE PLASMA CONCENTRATIONS OF THYROID-STIMULATING HORMONE AND PROLACTIN, FOLLOWING STIMULATION OF THE ROSTRAL HYPOTHALAMUS IN ADULT FEMALE RATS

1981 ◽  
Vol 89 (3) ◽  
pp. 379-387 ◽  
Author(s):  
D. J. SAPHIER ◽  
R. G. DYER
Keyword(s):  
Adult Female ◽  
Median Eminence ◽  
Monosodium Glutamate ◽  
Plasma Concentrations ◽  
Female Rats ◽  
Mediobasal Hypothalamus ◽  
Adult Rats ◽  
Thyrotrophin Releasing Hormone ◽  
Rostral Hypothalamus ◽  
Stimulation Of

Action potentials were recorded from 174 neurones in the mediobasal hypothalamus of ovariectomized adult female rats exposed neonatally to monosodium glutamate (MSG) and from 145 neurones in control rats. All of the animals, which were anaesthetized with urethane, had been ovariectomized for at least 3 weeks and received two injections of oestradiol benzoate (20 μg/100 g body weight, i.m.) 72 h and immediately before the recording experiments. The response of each neurone to electrical stimulation of the median eminence and rostral hypothalamus (preoptic and anterior hypothalamic areas; PO/AH) was analysed. The most striking feature of the results obtained was the significant (P < 0·001) loss of inhibitory responses in those neurones remaining in the adult rats after neonatal treatment with MSG. The loss of inhibitory responses applied to both stimulation sites. In each rat the response of one neurone, which was antidromically identified as projecting to the median eminence, was recorded before and during stimulation of the PO/AH at 50 Hz for 30 s in every min for 15 min. Before and after this stimulation blood was collected from a jugular vein for estimation by radioimmunoassay of concentrations of prolactin and TSH. In the MSG-treated rats significantly (P < 0·05) fewer neurones were inhibited by the 50 Hz stimulation than in control rats. In control rats the plasma concentrations of prolactin nearly quadrupled as an immediate consequence of this treatment, whereas in MSG-treated rats plasma concentrations barely doubled. However, in the MSG-treated rats plasma concentrations of prolactin continued to rise after stimulation ceased, possibly as a consequence of enhanced secretion of thyrotrophin releasing hormone.

Responses of neurons in VPL and VPL-VL region of the cat to algesic stimulation of muscle and tendon

1983 ◽  
Vol 49 (3) ◽  
pp. 649-661 ◽  
Author(s):  
K. D. Kniffki ◽  
K. Mizumura
Keyword(s):  
Electrical Stimulation ◽  
Mechanical Stimulation ◽  
Receptive Fields ◽  
Transitional Zone ◽  
The Other ◽  
Group Iii ◽  
Group I ◽  
Nociceptive Information ◽  
Noxious Mechanical Stimulation ◽  
Stimulation Of

1. The responses evoked by electrical stimulation of cutaneous and muscle nerves, by noxious and innocuous mechanical stimulation of muscle, tendon, and cutaneous tissues, and by intra-arterial (ia) injection of algesic substances (potassium, bradykinin) into arteries supplying the gastrocnemius-soleus muscle (GS) were studied in single neurons located in the ventroposterolateral nucleus (VPL) and in the transitional zone between VPL and the ventrolateral nucleus (VL) of cats lightly anesthetized with thiopenthal. Such chemical stimulation of the muscles has been shown to activate muscular groups III and IV axons specifically (43, 44) and presumably is nociceptive in character (14, 17, 31). 2. One hundred eight neurons were tested. Eighty-three of the units responded only to various types of cutaneous stimulation of the hindlimb. The other 25 responded to algesic stimulation of muscle and/or tendon. Of these latter 25, 7 had no apparent cutaneous receptive field although 4 of them responded to electrical stimulation of the common peroneal and/or sural nerve. Thus, only three neurons responded exclusively to algesic chemical and noxious mechanical stimulation of the muscle. Of the other 18 neurons, 14 had cutaneous receptive fields restricted to the hindlimb and often responded to non-noxious repetitive light stroking and to noxious pinching with a high-frequency discharge. Four cells (two of which had cutaneous input only from low-threshold mechanoreceptors) had complex and large receptive fields extending to more than one limb. 3. Potassium was a more potent muscle receptor stimulant than bradykinin, the latter only weakly exciting 3 neurons of 24 tested with both substances. The responses to potassium were rapid (approximately 4.0 s in latency) and tended to be greater (have higher response rates) for the units that responded to cutaneous as well as muscle/tendon stimulation. 4. Most neurons that responded to noxious deep stimulation had a threshold for the GS nerve volley in the group III fiber range. The few neurons with thresholds slightly below the group III range did not respond to activation of group I or II muscle spindle afferents by intra-arterial application of succinylcholine or by stretching the muscle. 5. Neurons with responses to any of the muscle, tendon, or cutaneous nociceptive stimuli were located at the ventral and dorsal periphery of VPL and in the VPL-VL transitional zone. 6. These results strongly suggest that there exist regions within the lateral diencephalon of cats that are capable of processing nociceptive information and that these regions are located at the periphery of VPL.

Ovulation Induced by Hypothalamic Stimulation in the Anesthetized Rat

1958 ◽  
Vol 195 (1) ◽  
pp. 171-174 ◽  
Author(s):  
Vaughn Critchlow
Keyword(s):  
Electrical Stimulation ◽  
Critical Period ◽  
Hypothalamic Stimulation ◽  
Female Rats ◽  
Bilateral Stimulation ◽  
Optic Chiasma ◽  
Estrous Cycles ◽  
Pentobarbital Anesthesia ◽  
Stimulation Of

In the present study, employing 38 female rats with normal estrous cycles, electrical stimulation during pentobarbital anesthesia was effective in inducing ovulation. It was found that bilateral stimulation of the hypothalamus in anesthetized proestrous rats during the ‘critical period’ and within certain spatial and current limitations consistently caused ovulation. The area that appears most responsive is medially situated in the ventral hypothalamus, between the optic chiasma and the infundibular stalk.

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