Effect of Electrical Stimulation of the Preoptic Area on Plasma LH Concentrations in Proestrous Rats

Cramer, O. M.; Barraclough, Charles A.

doi:10.1210/endo-88-5-1175

Cited by 43 publications

(16 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has been shown, us ing pharmacological methods, that these two amines are in timately involved in mechanisms which control the activity of the LH-RH neuronal network, and these mechanisms may reside within the MPO [1,4,13,28]. The observation that E release rates into the MPO are different from NE release points to the fact that these two amines are utilized from different neuronal networks confirming morphologi cal evidence [14].…”

Section: Discussionmentioning

confidence: 67%

See 1 more Smart Citation

Preoptic Catecholamine, GABA, and Glutamate Release in Ovariectomized and Ovariectomized Estrogen-Primed Rats Utilizing a Push-Pull Cannula Technique

et al. 1985

View full text Add to dashboard Cite

The push-pull cannula technique was used to evaluate the role of the medial preoptic/anterior hypothalamic area (MPO) in regulating pituitary luteinizing hormone (LH) and prolactin release. The concentrations of the three catecholamines – dopamine, norepinephrine (NE), epinephrine (E) – and gamma-aminobutyric acid (GABA) and glutamate could be measured in 15-min fractions at which interval blood samples for LH and prolactin determination were also collected. Comparison of neurotransmitter release rates into the MPO were made between ovariectomized and ovariectomized estradiol benzoate treated rats. Release of the neurotransmitters occurred in a pulsatile manner, the release episodes for each transmitter appeared to be independent of the others. No direct correlation between neurotransmitter release episodes and blood LH or prolactin levels could be established. The release of GABA was significantly lower and that of NE and E higher in ovariectomized animals in comparison to estrogen-primed ovariectomized animals under negative feedback conditions. In the afternoon, however, when the estrogen stimulated LH and prolactin release, preoptic GABA release was low, whereas preoptic NE and particularly E release rates were high. Conspicuously high dopamine and NE release episodes were observed in estrogen-primed animals at noon, i.e., prior to the expression of the positive feedback signal. This may reflect a biochemical correlate to the so-called critical period. No consistent differences between ovariectomized and ovariectomized estradiol-17β benzoate treated animals were observed for preoptic glutamate release rates. The data show that preoptic GABA release rates show generally an inverse pattern to NE and E release and therefore also to blood LH and prolactin levels. No direct mathematical correlation between any of the neurotransmitter release rates and blood hormone levels could be established.

show abstract

Section: Discussionmentioning

confidence: 67%

“…In the rat the majority of luteinizing hormone releasing hormone (LH-RH) neurons are located in this structure [7], stimulation of M PO causes LH and prolactin release [4,28], and the turnover rates of norepinephrine (NE) in this struc ture correlate well with blood LH levels [1. 13, 15, 27].…”

mentioning

confidence: 99%

Preoptic Catecholamine, GABA, and Glutamate Release in Ovariectomized and Ovariectomized Estrogen-Primed Rats Utilizing a Push-Pull Cannula Technique

et al. 1985

View full text Add to dashboard Cite

show abstract

“…The ef fectiveness of NT in stimulating LH release was also tested in nor-Ferris/ Pa n/Singer/Boyd/Carra way /Leeman Time, min mal cycling rats anesthetized with Dial-urethane on the morning of proestrus. The response to electrochemical [8] and electrical [4] stimulation of the MPOA or exogenous administration of LHRH [8] as measured by the release of LH is enhanced at this time of the estrous cycle. These animals had had two consecutive 4-day estrous cycles as determined by vaginal histology prior to use.…”

Section: Methodsmentioning

confidence: 91%

Stimulation of Luteinizing Hormone Release after Stereotaxic Microinjection of Neurotensin into the Medial Preoptic Area of Rats

et al. 1984

View full text Add to dashboard Cite

Neurons immunoreactive to luteinizing hormone-releasing hormone (LHRH) are localized to the medial preopticoseptal region of the rat hypothalamus, an area known to be essential for the regulation of the surge of luteinizing hormone (LH) that precedes ovulation. The effect of neurotensin (NT) on circulating LH levels following its discrete microinjection into this region was evaluated. Within 30 min after the stereotaxic microinjection of 40 ng of NT in 50 nl into the medial preoptic area (MPOA) just rostral to the organum vasculosum of the lamina terminalis in ovariectomized (OVX), anesthetized rats, plasma LH levels rose from 417 ± 36 to 923 ± 113 ng/ml (p < 0.001). There was also a significant increase (p < 0.001) in plasma LH levels following the microinjection of 50 ng of norepinephrine in 50 nl in this same site. Similarly, levels of LH increased from 48 ± 7 to 110 ± 19 ng/ml (p < 0.004) following the microinjection of NT into the rostral MPOA on the morning of proestrus in anesthetized rats. In contrast, saline, substance P, leuenkephalin and LHRH microinjected in the rostral MPOA of OVX rats had no significant effect on circulating levels of LH. The microinjection of NT 0.4 mm rostral or caudal to this area was also without effect. The presence of two binding sites with K_ds of 4.2 and 29 nM and site concentrations of 0.11 and 0.68 pmol/mg in tissue homogenates of the rostral MPOA were also established. These data suggest a role for NT in the central regulation of LH release.

show abstract

“…Several laboratories have examined the distribution of LHRH in specific brain regions using a microdissection procedure originally described by Palkovits (6). Hypothalamic areas previously implicated by lesion (7)(8)(9) and stimulation studies (10)(11)(12)(13) to be involved in LH release more recently have also been shown to contain LHRH-producing neurons. Besides identifying LHRH in tissue obtained from the preopticosuprachiasmatic anterior hypothalamic tuberoinfundibular system, this hormone also is localized, in varying amounts, in brain regions thought to have little to do with the release of LH and FSH (14)(15)(16) (Table 1); in these extrahypothalamic regions, it may behave as a neurotransmitter substance.…”

Section: A Lhrh Delivery Systemmentioning

confidence: 99%

The Role of Catecholamines in the Regulation of Pituitary Luteinizing Hormone and Follicle-Stimulating Hormone Secretion

1982

Self Cite

View full text Add to dashboard Cite

Effect of Electrical Stimulation of the Preoptic Area on Plasma LH Concentrations in Proestrous Rats

Cited by 43 publications

References 0 publications

Preoptic Catecholamine, GABA, and Glutamate Release in Ovariectomized and Ovariectomized Estrogen-Primed Rats Utilizing a Push-Pull Cannula Technique

Preoptic Catecholamine, GABA, and Glutamate Release in Ovariectomized and Ovariectomized Estrogen-Primed Rats Utilizing a Push-Pull Cannula Technique

Stimulation of Luteinizing Hormone Release after Stereotaxic Microinjection of Neurotensin into the Medial Preoptic Area of Rats

The Role of Catecholamines in the Regulation of Pituitary Luteinizing Hormone and Follicle-Stimulating Hormone Secretion

Contact Info

Product

Resources

About