### CHRM4 Gene Overview

**Gene Symbol:** CHRM4  
**Location:** Human chromosome 11 (11q13.5)  
**Function:** CHRM4 encodes the muscarinic acetylcholine receptor M4, which is a member of the G protein-coupled receptor (GPCR) family. It primarily mediates inhibitory responses through the inhibition of adenylate cyclase and affects various signaling pathways, influencing neuronal and cellular activities in both the central and peripheral nervous systems.

### 1. Associated Genes
While the summaries do not explicitly mention any associated genes, CHRM4 may be functionally linked to other genes involved in cholinergic signaling or G protein-coupled receptor regulation. Notably, these might include:
- **GRK2** (G protein-coupled receptor kinase 2) – involved in the phosphorylation and desensitization of GPCRs, including muscarinic receptors.
- **ADCY** genes (Adenylyl cyclase family) – since CHRM4's primary transducing effect is inhibition of adenylate cyclase, its functions are closely tied to these genes.

### 2. Aging and Age-Related Diseases
Research has indicated that cholinergic signaling, including pathways involving muscarinic receptors like CHRM4, may have implications in age-related cognitive decline and neurodegenerative disorders such as:
- **Alzheimer's Disease**: Dysregulation of cholinergic systems is often observed; muscarinic receptors are considered potential targets for therapeutic intervention.
- **Parkinson’s Disease**: Alterations in cholinergic signaling mechanisms may also play a role in the pathophysiology of this condition.
- General cognitive decline associated with aging may reflect changes in muscarinic receptor signaling.

### 3. Drug Interactions
CHRM4 is known to interact with several drugs and drug classes, particularly those acting on the cholinergic system. These include:
- **Anticholinergics**: Drugs like atropine and scopolamine, which have inhibitory effects on cholinergic neurotransmission.
- **Muscarinic Agonists**: Agents such as arecoline that can activate muscarinic receptors, affecting various physiological responses.
- **Centrally Acting Anticholinergics**: Clinically used in conditions like overactive bladder and Parkinson's disease, impacting muscarinic receptor modulation.

### 4. Pathways and Biological Processes
CHRM4 is involved in several pathways and biological processes, such as:
- **G protein-coupled receptor signaling**: Specifically mediating responses via G proteins and affecting second messenger systems.
- **Cholinergic signaling pathway**: Contributes to various physiological functions throughout the nervous system.
- **Regulation of neuronal signaling**: Modulates neurotransmitter release and contributes to synaptic plasticity and cognitive functions.
- **Inhibition of adenylate cyclase activity**: A key mechanism influencing cellular responses to acetylcholine.
- **Phosphoinositide signaling**: Involvement in breakdown and signaling pathways downstream of phosphoinositides, affecting cellular calcium levels and other cellular responses.

### Conclusion
The CHRM4 gene plays a significant role in cholinergic signaling as part of the muscarinic receptor family and may be linked to various physiological and pathophysiological conditions, particularly those related to aging and neurodegenerative diseases. Its interactions with specific drug classes and involvement in crucial signaling pathways further establish its functional importance in both health and disease contexts.