Electrical Stimulation of Ventral versus Dorsal Mesencephalic Tegmental Areas in the Conscious Rat: Effects on Luteinizing Hormone Release
Bibliographic record
Abstract
This study examined the effect of electrical stimulation of the ventral mesencephalic tegmentum versus the dorsal tegmentum region on blood LH levels in freely moving, ovariectomized (OVX) rats, as well as in OVX, estrogen-primed rats. In OVX rats, electrical stimulation (with parameters of 30 Hz, 0.4-msec biphasic pulses, 50-100 microA and 10 s on/off for 1 h) of the ventral tegmentum region with the aim of activating the ventral noradrenergic tract (VNT) failed to affect the pulsatile pattern of blood LH levels characteristic of OVX animals. In sharp contrast, electrical stimulation of the dorsal tegmentum region inside the ascending dorsal noradrenergic tract (DNT) markedly inhibited pulsatile LH release in OVX rats; the mean blood LH levels during the 1-hour stimulation period were significantly decreased when compared with prestimulation control values. Electrical stimulation in the same region near but outside the DNT was ineffective. In OVX rats primed with estradiol benzoate, electrical stimulation in the ventral or dorsal tegmentum region failed to alter the low, nonpulsatile blood levels of LH. The results in OVX rats suggest that selective activation of the ascending noradrenergic fibres of the DNT but not the VNT can inhibit pulsatile LH release in the awake, freely moving animal. These data further support the possible existence of an inhibitory noradrenergic system in the modulation of LH release.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".