Morphometric studies of the axonal processes and nerve cell bodies of the spinal dorsal root ganglion neurons in rats

The primary sensory neuron plays an important role in both somatic and visceral afferent nervous functions.In this study.The primary sensory neuron was morphometrically evaluated to reveal1)the subclasses of nerve fibers at the level of the sural nerve and trird sacral dorsal root and of nerve cell bodies at the third sacral dorsal root ganglion in control rats and2)the subclasses of nerve fibers and nerve cell bodies lost in capsaicin-intoxicated rats.In the sural nerve the numbers per nerve of large(&lt；4.3&lt；micrn&gt；m)，small myelinated(&lt；equal or less than&gt；4.3&lt；micrn&gt；m)and unmyelinated fibers were660&lt；plus-minus&gt；118(mean&lt；plus-minus&gt；standard deviation)，377&lt；plus-minus&gt；46and3，856&lt；plus-minus&gt；570，respectively，In the third sacral dorsal slumge of the large；Micrn&gt；m)，small myelinated(&lt；equal or less than&gt；m)and unmyelinated fibers were641&lt；plus-minus&gt；82，667&lt；plus-minus&gt；126and3，303&lt；plus-minus&gt；541，respectively.In the third sacral dorsal root ganglion，the numbers per ganglion of large and small nerve cell bodies were613&lt；plus-minus&gt；115and1，684&lt；plus-minus&gt；72，r~纯黑芥末，2In rats administered with the single subcutaneous capsaicin(50 mg/kg)，the number per nerve of unmyelinated fibers was1，232&lt；plus-minus&gt；233 and sificantly(P&lt；0.0001)less ss the control the fibers was 1，232&lt；plus-minus&gt；233 and sificantly(P&lt；0.0001)81and895&lt；plus-minus&gt；245，respectively and significantly(P&lt；0.04and P&lt；0.0001，respectively)less than in control in the third sacral dorsal root and the number of small nerve cell bodies per ganglion was860&lt；plus-minus&gt；285and significantly(P&lt；0.0003)less than in control.Therefore，the small spinal sensory neuron degenerates and is lost in capsaicin-intoxicat377&lt；pluThe morphometric analysis of the primary sensory neuron is useful for the studies of the pathogenetic mechanisms of the numan and experimental neuropathies.

The primary sensory neuron plays an important role in both somatic and visceral afferent nervous functions. In this study. the primary sensory neuron was morphometrically evaluated to reveal 1)the subclasses of nerve fibers at the level of the sural nerve and trird sacral dorsal root and of nerve cell bodies at the third sacral dorsal root ganglion in control rats and 2)the subclasses of nerve fibers and nerve cell bodies lost in capsaicin-intoxicated rats. In the sural nerve the numbers per nerve of large (<4.3<micrn>m), small myelinated (<equal or less than>4.3<micrn>m) and unmyelinated fibers were 660 <plus-minus> 118 (mean <plus-minus> standard deviation), 377 <plus-minus> 46 and 3,856 <plus-minus> 570, respectively, In the third sacral dorsal root, the numbers per root of large (>6.3<micrn>m), small myelinated (<equal or less than>m) and unmyelinated fibers were 641 <plus-minus> 82, 667 <plus-minus> 126 and 3,303 <plus-minus> 541, respectively. In the third sacral dorsal root ganglion, the numbers per ganglion of large and small nerve cell bodies were 613 <plus-minus> 115 and 1,684 <plus-minus> 72, r~ホモ ヘンカシ 、 2In rats administered with the single subcutaneous capsaicin (50 mg/kg), the number per nerve of unmyelinated fibers was 1,232 <plus-minus> 233 and significantly (P<0.0001) less than in control in the sural nerve, the numbers of small myelinated and unmyelinated fibers per root were 542 <plus-minus> 81 and 895 <plus-minus> 245, respectively and significantly (P<0.04 and P<0.0001, respectively) less than in control in the third sacral dorsal root and the number of small nerve cell bodies per ganglion was 860 <plus-minus> 285 and significantly (P<0.0003) less than in control. Therefore, the small spinal sensory neuron degenerates and is lost in capsaicin-intoxicat377 <pluThe morphometric analysis of the primary sensory neuron is useful for the studies of the pathogenetic mechanisms of the numan and experimental neuropathies.