Gastrin‐releasing peptide acts via postsynaptic BB<sub>2</sub> receptors to modulate inward rectifier K<sup>+</sup> and TRPV1‐like conductances in rat paraventricular thalamic neurons
Bibliographic record
Abstract
Key points Gastrin‐releasing peptide (GRP) is a mammalian bombesin‐like peptide that is widely distributed in the CNS. Whereas GRP is known to have a predominant excitatory action on neurons, details of the underlying membrane mechanism remain largely undefined. We investigated GRP‐affected receptors and ionic conductances in the midline paraventricular thalamic nucleus, a brain region densely innervated by GRP‐like immunoreactive fibres. Perforated patch clamp recording in acute brain slices showed that exposure of paraventricular thalamic nucleus neurons to low nanomolar concentrations of GRP resulted in membrane depolarization with rhythmic burst or tonic firing. These responses were due to a postsynaptic bombesin type 2 receptor‐mediated simultaneous suppression of a Ba 2+ ‐sensitive inward rectifier K + conductance and activation of a non‐selective cation conductance with transient receptor potential vanilloid 1‐like properties. The data provide details on the nature of the receptor and ionic conductances involved in GRP's excitatory influence on midline thalamic neurons. Abstract Gastrin‐releasing peptide (GRP) is a bombesin‐like peptide with a widespread distribution in mammalian CNS, where it has a role in food intake, circadian rhythm generation, fear memory, itch sensation and sexual behaviour. While it has been established that GRP predominantly excites neurons, details of the membrane mechanism involved in this action remain largely undefined. We used perforated patch clamp recording in acute brain slice preparations to investigate GRP‐affected receptors and ionic conductances in neurons of the rat paraventricular thalamic nucleus (PVT). PVT is a component of the midline and intralaminar thalamus that participates in arousal, motivational drives and stress responses, and exhibits a prominence of GRP‐like immunoreactive fibres. Exposure of PVT neurons to low nanomolar concentrations of GRP induced sustained TTX‐resistant membrane depolarizations that could trigger rhythmic burst discharges or tonic firing. Membrane current analyses in voltage clamp revealed an underlying postsynaptic bombesin type 2 receptor‐mediated inward current that resulted from the simultaneous suppression of a Ba 2+ ‐sensitive inward rectifier K + conductance and activation of a non‐selective cation conductance with biophysical and pharmacological properties reminiscent of transient receptor potential vanilloid (TRPV) 1. A role for a TRPV1‐like conductance was further implied by a significant suppressant influence of a TRPV1 antagonist on GRP‐induced membrane depolarization and rhythmic burst or tonic firing. The results provide a detailed picture of the receptor and ionic conductances that are involved in GRP's excitatory action in midline thalamus.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".