Narishige SR-5R-HT / SR-6R-HT Stereotactic Instrument for Rat Neurosurgery

Overview

The Narishige SR-5R-HT and SR-6R-HT are high-precision stereotactic instruments engineered specifically for rat neurosurgical and electrophysiological applications. Built upon the proven mechanical architecture of Narishige’s SR-series, these models integrate ergonomic refinements and structural enhancements to improve head fixation stability, operator tactile feedback, and modular expandability. Unlike generic stereotactic frames, the SR-5R-HT and SR-6R-HT employ a dual-axis ear-bar anchoring system—comprising primary EB-3A ear bars and auxiliary EB-4N bars—that enables secure, reproducible skull immobilization while allowing single-hand clamping with real-time haptic verification of external auditory canal engagement. The instrument operates on classical stereotactic principles: orthogonal coordinate alignment (anterior–posterior, medial–lateral, dorsal–ventral) referenced to bregma or lambda landmarks, ensuring sub-millimeter positional repeatability essential for intracranial injections, electrode implantation, and optogenetic fiber placement in longitudinal rodent studies.

Key Features

• Optimized rat-specific head fixation: Fine-tuned EB-3A ear bars and slender EB-4N auxiliary bars ensure reliable engagement with rat temporal bone anatomy without tissue compression or slippage.
• Tactile confirmation interface: Operator fingertip feedback during EB-4N clamping allows immediate verification of proper external auditory canal seating—critical for minimizing inter-session variability.
• Miniaturized oral-nasal clamp: Low-profile jaw design matches the rostral morphology of adult Sprague-Dawley or Wistar rats, enabling unobstructed visualization of incisors and precise dental alignment.
• Three-degree-of-freedom adjustment: Independent micrometer-driven controls for anterior–posterior (AP), dorsal–ventral (DV), and medial–lateral (ML) positioning—each calibrated to 0.1 mm resolution with lockable vernier scales.
• Modular AP frame rail system: SR-5R-HT includes one standardized AP rail; SR-6R-HT features two parallel rails, permitting simultaneous mounting of multiple micro-manipulators, laser alignment guides, or custom-built accessories without mechanical interference.
• Stable base architecture: Cast aluminum base (400 × 300 × 110 mm) with vibration-dampening feet ensures rigidity during microinjection or patch-clamp procedures, even under extended-duration experiments.

Sample Compatibility & Compliance

Designed exclusively for adult rats (250–500 g), the SR-5R-HT and SR-6R-HT accommodate standard laboratory strains including Long-Evans, Fischer 344, and transgenic lines with typical cranial dimensions. The EB-3A/EB-4N ear bar configuration complies with widely adopted stereotactic atlases (e.g., Paxinos & Watson, 7th ed.) and supports alignment to both bregma and lambda coordinates. While the instrument itself is not a medical device, its mechanical precision and traceable adjustability support adherence to GLP-compliant experimental protocols where procedural consistency and audit-ready setup documentation are required. No electrical components or software are embedded—thus no electromagnetic compatibility (EMC) or IEC 61000 certification applies; however, the passive mechanical design ensures full compatibility with MRI-compatible surgical suites when non-ferromagnetic accessories are selected.

Software & Data Management

The SR-5R-HT and SR-6R-HT are fully manual, analog stereotactic systems with no integrated electronics, firmware, or digital interfaces. All positioning data—including AP/DV/ML coordinates, ear bar depth settings, and rail-mounted accessory configurations—are recorded manually in lab notebooks or electronic lab notebooks (ELNs) per institutional SOPs. This design eliminates dependencies on proprietary drivers or vendor-specific calibration files, ensuring long-term protocol portability across facilities and compliance with FDA 21 CFR Part 11 requirements when paired with validated ELN platforms that maintain audit trails, electronic signatures, and version-controlled experiment logs. Optional third-party digital calipers or optical encoders may be mounted externally for coordinate logging, though Narishige does not supply or validate such integrations.

Applications

• Intracerebral injection of viral vectors, tracers, or pharmacological agents with ≤0.2 mm targeting accuracy.
• Chronic implantation of bilateral microelectrode arrays or silicon probes for in vivo electrophysiology.
• Targeted optogenetic fiber optic cannula placement in deep brain nuclei (e.g., VTA, SNc, BLA).
• Stereotactic lesioning via electrolytic or excitotoxic methods under visual guidance.
• Combined use with intraoperative imaging (e.g., fluorescence-guided surgery) when mounted on compatible stereotaxic stages with translational compatibility.
• Training platform for neuroscience graduate students—emphasizing anatomical landmark identification, coordinate transformation, and mechanical dexterity.

FAQ

What is the difference between SR-5R-HT and SR-6R-HT?
The SR-6R-HT features two parallel anterior–posterior (AP) frame rails, enabling concurrent attachment of multiple manipulators or accessories; the SR-5R-HT has a single AP rail.
Are replacement ear bars available separately?
Yes—EB-3A (standard rat ear bars) and EB-4N (auxiliary ear bars) are orderable as consumable accessories through authorized Narishige distributors.
Can this instrument be used for mice?
No. The SR-5R-HT/SR-6R-HT is dimensionally optimized for rats; Narishige offers dedicated mouse models (e.g., SR-5M-HT) with scaled ear bars and clamps.
Is the base compatible with standard microscope stages?
The 400 × 300 mm footprint fits most large-bore stereomicroscope stages; optional adapter plates are available for custom integration with motorized stage controllers.
Does Narishige provide stereotactic atlas integration or coordinate conversion tools?
Narishige supplies printed alignment guides aligned to Paxinos & Watson; digital coordinate converters are maintained independently by academic labs and are not distributed by the manufacturer.