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1 , , 51 (1), Acta Physiologica Si nica (, ),, ,,, (5117 %) (111 %) (17 %) 85, : ; ; ; ; ; : R818, R8125,,,, [1 ],,,, [2, ] [,4 ],,,,,, (primary somatosensory cortex, S ), (neurobiotin),,, , kg (No ) :,

2 2 51, (40 mg/ kg), (greater splanchnic nerve, GSN ), ( 215 mm),, 11 12,, S GSN (AP, 2 mm ; L R, 4 mm) [5 ], , [6, ] m, mol/ L KCl, (Sigmar ) S GSN, RP 40 mv 5 min, MEZ28201 VC210,, A TAC250, X2Y GSN ms, ma, A C,,,, : 1 na 220 ms 1 Hz, 15 min, ( ), (70 m) 11 HRP Strepavidin, PBS, DAB,,, ( 1 ) 114, t, P < Fig11 Microp hotograp h of t he neu2 ron labelled by neurobiotin in S area lamina ( 85) Scale bar, 10 m (, ), GSN ( visceral nociceptive neurons, VNNs, %), ( non2visceral noci2 ceptive neurons, NVNNs, %) VNNs, VNNs ( specific visceronociceptive neurons, SVNNs), VNNs ( non2

3 1 : specific visceronociceptive neurons, NSVNNs) RP > 70 mv S GSN VNNs GSN VNNs, 6 ( 2) 2 S VNNs Fig12 Modes of biological electric activities of visceral noci2 ceptive neurons in S area A : Non2discharges in resting state1 B : Synaptic noise activites. C : Occasionally discharges. D : Continous tonic discharges. E : Rhythmic high frequence discharges. F : Pair2spikes., VNNs NVNNs,, 1 NVNNs VNNs 100 VNNs NVNNs, VNNs NVNNs,, VNNs NVNNs 1 S VNNs NVNNs Table 1 Comparison of partial characterisitics between VNNs and NVNNs Resting potential / mv Cells having discharge Cells without discharge Frequency of discharges Amplitude of discharges / mv Depth distributed H/ m VNNs ( n ) NVNNs ( n ) Statistic analysis ( n = 100) ( n = 100) P < ( n = 100) 2 ( n = 100) ( n = 45) ( n = 25) P < ( n = 45) ( n = 25) P > ( n = 45) ( n = 25) P < 0101 x s. P < 0101 significantly different from VNNs VNNs (1) : GSN, NSVNNs, 014 ma,, EPSP, 016 ma,, 016 ma, 115 GSN (2) VNNs : (51170 %) (111 %) (1710 %) VNNs,, ( EPSP) ( IPSP),, 5 ms, 70 ms, ms EPSP (018

4 ) ms ( n = 0) IPSP ( ) ms, ( n = 10) S [ EPSP( ) ms, IPSP( ) ms, n = 10 ] ( P : EPSP VNNs Fig1 Excitatory responses in variety of VNNs evoked by stimulating GSN A : Uni2EPSP. B : Poly2EPSPs. C : Spikes on EPSP. D : Uni2spike. E : Spikes on EPSP in spontaneous dis2 charges condition. F : Increased discharges (upper curve as control) 1 < 0101), SVNNs [ EPSP ( ) ms, n = 15 ] [ ( ) ms, n = 10 ] ( P < 0101), VNNs [ ( ) ms n = 50 ] [ ( ) ms n = 20 ] ( P < 0101 ), VNNs IPSP (1812 %) IP2 SP (91 %) : (1),,, 21 ( ) (2) : ( IPSP) ( 4) () : EPSP2IPSP 4, VNNs Fig14 Inhibitory responses of VNNs in S evoked by stimulating GSN A : Uni2IPSP. B : Double IPSPs. C : IP2 SP (in discharges). D : Poly IPSPs(in dis2 charges). E : Discharges vanished gradual2 ly. 212 GSN S VNNs, 1 mg/ kg, 1 min, min, 20 min VNNs, 10, 21 S 26 GSN, 2 [1 85 ( 2 %) ( 5), ], 7215 %,, 2, 20 ms,,

5 1 : 5, 5 Fig15 Convergence of splanchnic and in2 tercostal nerve upon t he same neuron The responses induced by stimulating GSN (latency 70 ms) ( A ) and intercostal nerve (latency 56 ms) ( B ) 11 GSN VNNs 1111 [,4, Follett ] GSN, S GSN, ms [8 A ], GNS S C2CEP, ( ) ms, C, [2, A ] VNNs 0 ms, 70 ms A, 140 ms C,, VNNs GSN, 1112 S ( P < 0101), C, C (21 ) EP2 SP2IPSP (4 ) 2 (29 ), [7, ], VNNs,,,, VNNs,, EPSP IPSP,,,,,,,

6 6 51, : [9 ] [10 ], 1212 VNNs NVNNs, NVNNs VNNs RP, VNNs, [14 ] 1, S : VNNs S,,, Neuroitin, VNNs, NVNNs [11 1 ( P < 0101), ] S GSN VNNs %, (2168 %), VNNs IPSP, VNNs,, VNNs,,,,,, VNNs, [1 ] Gebhart GF, Ness TJ. Mechanisms of visceral pain. In : Bond M, Charton J E, Wolf CJ Eds. Proceedings of the th World Congress on Pain. Amsterdam : Elsevier Science Publishers BV, 1991, [2 ] Chen PX ( ), Chen ZH ( ). Average evoked potential in the somatosensory cortex elicited by SPL A and C fiber imput. Acupunct Res ( ), 1987, 12 (2) : (in Chinese with English abstract). [ ] Follett KA, Dirks B. Characterization of responses of primary somatosensory cerebral cortex neurons to nox2 ious visceral stimulation in the rats. B rain Res, 1994, 656 (1) : [4 ] Follett KA, dirks B. Responses of neurons in ventrolateral orbital cortex to noxious visceral stimulation in the rat. B rain Res, 1995, 669 (2) : [5 ] Tyner CF. Splanchnic nerve activation of single cells in the cat s post2crucriate motosensory cortex. Ex p Neurol, 1979, 6 (1) : [6 ] Kang R. Convergence of sensory inputs in somatosensory cortex : Interactions from separate afferent. Ex p B rain Res, 1985, 57 : [7 ] Teng GX ( ), Gong YS ( ), Liu SJ ( ), et al. Influence of stimulation of nerve of hind limb on intracellular potentials of the neurons in primary sensory cortex of cat. J Chin Med U niv ( ), 1996, 25 (6) : (in Chinese with English abstract). [8 ] Sha L ( ), Ding W ( ), Teng GX ( ). Responses of neurons in the somatosensory area to electric stimulation of nerve peroneus communis. Acupunct Res ( ), 1992, 17 () : (in Chinese with English abstract).

7 1 : 7 [ 9 ] Linas RR. The intrinsic electrophysiological properties of mammalian neurons : Insights into central neu2 rons system function. Science, 1988, 242 : [10 ] Shepherd GM, Koch C. Introduction to synaptic circuits. In : Shepherd GM, ed. The S ynaptic Organiz a2 tion of the B rain. rd, ed. London : Oxford University Press, 1990, 1 1. [11 ] Lamour Y, Willer J C, Guilboud G. Rat somatosensory cortex : I. Characteristics of neuronal responses to noxious stimulation and comparison with responses to non2noxious stimulation. Ex p B rain Res, 198, 49 : [12 ] Yamamura H, Iwata K, Truboi Y, et al. Morphological electrophysiological properties of ACCx nociceptive neurons in rats. B rain Res, 1996, 75 : [ 1 ] Yamamoto T, Samejima A, Oka H. The mode of synaptic activation of pyramidal neuron in cat primary so2 matosensory cortex : an intracellullar HRP study. Ex p B rain Res, 1990, 80 : [ 14 ] Chen J H ( ), Teng GX ( ). Comparsion of membrane electrophysiological characteristics of vis2 ceral and non2visceronociceptive neurons in cortex S area. Chin Sci B ull ( ), 1998, 4 (14) : (in Chinese). Acta Physiologica Si nica Feb. 1999, 51 (1), 1 7 INTRACELL ULAR EL ECTROP HYSIOLOGICAL CHARACTERISTICS OF VISCERAL NOCICEPTIVE NEURONS IN CORTEX S AREA OF CATS CHEN J IN G2HON G, TEN G GUO2XI ( L aboratory of Neurophysiology, B rain Research Institute, China Medical U niversity, S henyang ) ABSTRACT In t he present work we investigated electrop hysiological properties of visceral nociceptive neurons in the primary somatosensory cortex (S ). Intracellular record2 ings of 851 neurons in the representing area of greater splanchnic nerve ( GSN) in S area were made in 22 cats. The neurons showed a variaty of modes in sponteneous discharges, which could be classified into visceral nociceptive neurons ( VNNs) and non2visceral nociceptive neurons ( NVNNs). VNNs (412) could be f urt her divided into specific and non2specific subtypes, wit h t hree distinct response modes : excitato2 ry, inhibitory, and mixed response. These responses were characterized by longer la2 tency and complex responsive fashion. In addition, 85 single convergence neurons in2 duced by input f rom GSN and intercostal nerve were observed. Neurobiotin was in2 jected into some of the cells by electrophoresis to identify the depth and morphology following recordings. The results indicated that VNNs were located in the S area. Key words : somatosensory cortex ; visceral ; nociceptive ; int racellular recording ; labeling ; pain Supported by the National Natural Science Foundation of China (No )