The ADRA1D gene encodes the alpha-1D adrenergic receptor, which is part of a larger family of G protein-coupled receptors (GPCRs). These receptors play pivotal roles in various physiological processes including vascular tone regulation, neurotransmission, and cellular proliferation. Here is a detailed overview of the gene ADRA1D, taking into account your requests:

### 1. Associated Genes
The ADRA1D gene is associated with several other genes, particularly those involved in adrenergic signaling and pathways that modulate its activity. Some of the associated genes include:
- **ADRA1A**: Encodes the alpha-1A adrenergic receptor.
- **ADRA1B**: Encodes the alpha-1B adrenergic receptor.
- **GNAQ** and **GNA11**: Encode the G proteins that are activated by the alpha-1 adrenergic receptors.
- **RGS2**: Encodes a regulator of G protein signaling that modulates the signaling pathways of G protein-coupled receptors.

### 2. Aging and Age-Related Diseases
The ADRA1D gene has been implicated in multiple biological processes and may have associations with certain age-related conditions:
- **Age-Related Cardiovascular Diseases**: Dysregulation of alpha-1 adrenergic receptors has been associated with hypertension and other cardiovascular disorders which are more prevalent with aging.
- **Neurodegenerative Diseases**: Changes in adrenergic signaling, including that potentially mediated by ADRA1D, have been linked to various neurodegenerative diseases, possibly influencing neuronal health and synaptic plasticity with age.
- **Metabolic Disorders**: Altered adrenergic receptor signaling may affect metabolic pathways, with potential implications for age-related disorders such as obesity and type 2 diabetes.

### 3. Drug Interactions
The ADRA1D receptor is a target for several drugs and drug classes that modulate adrenergic activity. Notable ones include:
- **Alpha-1 Adrenergic Antagonists**: Drugs such as prazosin and doxazosin are selective for alpha-1 adrenergic receptors and are primarily used in the treatment of hypertension and benign prostatic hyperplasia.
- **Alpha-1 Adrenergic Agonists**: Medications like phenylephrine stimulate the receptor and are used as vasoconstrictors in clinical and emergency situations.
- **Beta-Blockers**: While these primarily target beta-adrenergic receptors, some may have indirect effects on alpha receptors and are used in managing cardiovascular conditions.

### 4. Pathways and Biological Processes
ADRA1D is involved in a diverse array of biological pathways, including:
- **Calcium Signaling Pathway**: The activation of ADRA1D leads to the influx of extracellular calcium, influencing various cellular processes.
- **Phosphatidylinositol Signaling Pathway**: It is involved in the generation of inositol trisphosphate (IP3) and diacylglycerol (DAG), crucial for cellular signaling and metabolic responses.
- **Vascular Smooth Muscle Contraction**: ADRA1D plays a significant role in regulating the contraction of vascular smooth muscle cells, contributing to blood pressure regulation.
- **Cell Growth and Proliferation**: Activation of this receptor has mitogenic effects, meaning it can promote cell growth and division.

### Summary
The ADRA1D gene is a key player in adrenergic signaling pathways and has significant implications in cardiovascular health, neurobiology, and other physiological functions. Its interactions with other genes, drugs, and pathways highlight its importance in both normal physiology and disease states, particularly in aging populations. Understanding the role of ADRA1D could lead to advanced therapeutic strategies targeting various age-related diseases.