The GRM8-AS1 gene, also known as "GRM8 antisense RNA 1," is a relatively recently identified long non-coding RNA (lncRNA) that is expressed in various tissues and is thought to play a role in the regulation of gene expression, particularly in relation to the GRM8 gene, which encodes the metabotropic glutamate receptor 8. Below is a detailed overview based on your queries:

### 1. Associated Genes
While specific associations may vary in literature, GRM8-AS1 is mainly linked with the GRM8 gene, given its role as an antisense RNA. However, associations with other genes involved in neuroactive ligand-receptor interactions, synaptic transmission, and neurodevelopment are likely due to the functional pathway of the GRM8 receptor itself. Some notable genes that may be contextually associated include:
- **GRM7**: Another metabotropic glutamate receptor.
- **GRIA1**: Glutamate receptor, ionotropic, AMPA 1.
- **GABBR1**: Gamma-aminobutyric acid receptor, which could interact in synaptic signaling pathways.

### 2. Aging and Age-related Diseases
Research on GRM8-AS1 specifically related to aging or age-related diseases is limited. However, the GRM8 gene itself has been implicated in neurodegenerative diseases, such as Alzheimer's and Parkinson's disease, where glutamate signaling is thought to be dysregulated. Dysregulation of lncRNAs like GRM8-AS1 may contribute to the pathophysiology of age-related cognitive decline. Additionally, alterations in lncRNA expression patterns, including potential effects on GRM8-AS1, have been documented in aging and age-associated diseases.

### 3. Drug Interactions
As of October 2023, specific drug interactions with GRM8-AS1 have not been extensively reported in the literature. However, drugs that target the GRM8 receptor directly, such as:
- **MGLUR8 antagonists**: These are under investigation for their therapeutic potential in modulating glutamate signaling in various neurological disorders.
- **Potential psychoactive substances** that alter glutamate signaling may indirectly affect pathways influenced by GRM8-AS1 due to its regulatory role.

### 4. Pathways and Biological Processes
GRM8-AS1, as an lncRNA, is involved in several biological processes, particularly regarding gene regulation:
- **Regulation of gene expression**: Through various mechanisms, including chromatin remodeling and modulation of transcriptional activity.
- **Neurological processes**: Modulating pathways related to synaptic plasticity and neurotransmitter release.
- **Glutamate signaling pathway**: Given its proximity to the GRM8 gene, it's involved in modulating glutamate-mediated synaptic functions.

In silico analyses have suggested involvement in several pathways tied to neuronal development and function, potentially impacting overall brain health and neurodegenerative conditions.

### Summary
The GRM8-AS1 gene is a regulatory lncRNA associated with the GRM8 receptor, potentially implicating it in pathways related to neurodegenerative diseases, particularly due to its regulatory functions in glutamate signaling. Further research is needed to establish more explicit connections relating to drug interactions, aging, and complete biological pathway involvement.