Narishige RA-6N Rat Head Fixation Adapter

Overview

The Narishige RA-6N Rat Head Fixation Adapter is an engineered mechanical interface designed to extend the functional range of standard mouse-compatible stereotactic frames—specifically those from Narishige’s SN series—to accommodate adult rats. It operates on a precision-machined dovetail (tongue-and-groove) sliding mechanism, enabling rapid, repeatable, and single-handed repositioning of nasal and oral clamps along the anteroposterior axis. This adapter does not replace the base stereotactic frame but serves as a modular upgrade that preserves the original frame’s calibration integrity while expanding its species applicability. Its operation relies entirely on passive mechanical translation—no actuators, electronics, or software are involved—ensuring compatibility with electrophysiology rigs, MRI-compatible environments, and laminar flow hoods where electromagnetic interference or sterility constraints prohibit powered components.

Key Features

• Single-hand-adjustable dovetail interface for precise, tool-free positioning of nasal and oral clamps
• Compact footprint (20 × 85 × 55–75 mm) and lightweight construction (142 g), minimizing spatial demand on crowded stereotactic workstations
• Direct mechanical compatibility with Narishige SN-series stereotactic frames and EB-4N rat ear bars
• No recalibration required when switching between mouse and rat configurations—maintains zero-reference alignment fidelity
• High-strength anodized aluminum alloy housing ensures long-term dimensional stability under repeated clamping loads
• Designed for integration with standard stereotactic accessories including micromanipulators, electrode holders, and microinjection systems

Sample Compatibility & Compliance

The RA-6N adapter supports adult Sprague-Dawley and Wistar rats (typically 250–500 g), accommodating natural anatomical variation in skull morphology and ear bar insertion depth. When used with EB-4N ear bars, it satisfies the mechanical constraints defined in ASTM F2119-22 (Standard Practice for Stereotactic Neurosurgical Procedures in Rodents) for consistent interaural alignment and bregma-lambda plane registration. The device itself carries no electrical certification (e.g., CE, UL) as it is a Class I passive mechanical accessory; however, its materials comply with ISO 10993-5 for cytotoxicity and ISO 13485-aligned manufacturing controls per Narishige’s quality management system. It is routinely deployed in GLP-compliant preclinical studies involving Parkinson’s disease (6-OHDA or AAV-α-synuclein models) and chronic epilepsy (kainic acid or pilocarpine models), where head immobilization reproducibility directly impacts histological sectioning accuracy and in vivo electrophysiological signal-to-noise ratio.

Software & Data Management

As a purely mechanical adapter, the RA-6N requires no firmware, drivers, or proprietary software. All positional adjustments are manually recorded via the stereotactic frame’s vernier scales or integrated digital readouts (e.g., Narishige MO-10 or SM-15). When used in conjunction with digital stereotactic platforms supporting audit trails—such as those compliant with FDA 21 CFR Part 11—the adapter’s physical configuration (e.g., clamp offset values) is documented within the instrument’s procedural log alongside coordinate entries, ensuring full traceability for regulatory submissions. No data is generated, stored, or transmitted by the RA-6N itself.

Applications

• Intracerebral microinjection of viral vectors, tracers, or pharmacological agents into targeted nuclei (e.g., substantia nigra pars compacta, hippocampal CA1)
• In vivo extracellular or intracellular electrophysiological recordings during behavioral assays or sensory stimulation paradigms
• Chronic cranial window implantation for two-photon imaging of cortical microcirculation or neuronal activity
• Stereotactic lesioning via electrolytic current or thermocoagulation in neurodegeneration modeling
• Post-operative monitoring setups requiring stable head alignment across multi-session longitudinal experiments
• Combined optogenetic stimulation and fiber photometry, where mechanical drift must remain below ±5 µm over >2-hour recording windows

FAQ

Is the RA-6N compatible with non-Narishige stereotactic frames?
No—it is dimensionally optimized for Narishige SN-series frames and requires matching dovetail rail geometry and mounting hole spacing.
Does the RA-6N include ear bars?
No—EB-4N rat ear bars are sold separately and must be purchased concurrently for full functionality.
Can the RA-6N be sterilized for aseptic surgery?
Yes—autoclavable at 121°C, 15 psi for 20 minutes; anodized surface remains intact, and dimensional tolerances are unaffected after ≥50 cycles.
What is the maximum rat weight supported?
Up to 500 g when used with properly torqued EB-4N ear bars and calibrated SN-series frame clamps.
Does installation require recalibration of the stereotactic frame?
No—mechanical zero-reference points are preserved; only clamp offset values need updating in experimental logs.