# Experiment #22: Adenosine A2A Receptor Antagonism for HD MSN Protection

**Date:** October 04, 2026
**Model:** not run
**Version:** 1
**First run:** October 04, 2026, no model called

## Hypothesis

The checked-in script states a research question. That question is not a result of this run:

1. What is the mechanistic basis for A2A receptor overactivation in HD striatal MSNs? 2. Does istradefylline rescue HD phenotypes in R6/2 or zQ175 models? 3. What is the A2AR-cAMP-PKA-BDNF signaling cascade in MSN vulnerability? 4. How does A2A antagonism compare with or complement PDE10A inhibition? 5. Is there epidemiological evidence linking caffeine intake to delayed HD onset? 6. What is the druggability and CNS pharmacology of A2A antagonists? 7. Are there HD-specific A2A receptor expression changes in post-mortem brain? 8. What combination strategies (A2A + PDE10A, A2A + NR) might synergize?

## Method

Confirmed `src/run_experiment_22_adenosine_a2a_msnprotection.py` is present and that no results file for experiment 22 existed before this write-up. The script describes a PubMed-to-local-LLM pipeline. It was not executed. `llm_blocker()` returned: Blocked: Ollama is not reachable at http://localhost:11434 (ConnectionError). Set OLLAMA_BASE_URL to a running server, or set GEMINI_API_KEY (or GOOGLE_API_KEY) with HD_LLM_BACKEND=aistudio. No model output was generated.

## Result

No papers were fetched for this experiment. No model was called. No scores, rankings, or biological findings were computed. The finished outcome is that the run is blocked before data collection.

## Log

- Script present: yes
- Prior result artifact: none
- Model calls: 0
- Papers fetched by this run: 0

updated by writing a finished account of the unexecuted script. No findings were invented.