심맥관계 활동과 관련있는 연수 척수로 세포에 작용하는 신경흥분전달물질에 대한 연구

A Study on the Neurotransmitters Acting on the Medullospinal Tract Cells Related to the Cardiovascular Activity

  • 서동만 (울산대학교 의과대학 흉부외과학교실) ;
  • 김상정 (서울대학교 의과대학 생리학교실) ;
  • 임원일 (서울대학교 의과대학 생리학교실) ;
  • 김전 (서울대학교 의과대학 생리학교실) ;
  • 김종환 (서울대학교 의과대학 흉부외과학교실)
  • Seo, Dong-Man (Department of Thoracic and Cardiovascular Surgery, College of Medicine, Ulsan University) ;
  • Kim, Sang-Jeong (Department of Physiology, College of Medicine, Seoul National University) ;
  • Lim, Won-il (Department of Physiology, College of Medicine, Seoul National University) ;
  • Kim, Jun (Department of Physiology, College of Medicine, Seoul National University) ;
  • Kim, Chong-Whan (Department of Thoracic and Cardiovascular Surgery, College of Medicine, Seoul National University)
  • 발행 : 1998.05.01

초록

본 연구는 동맥혈압의 조절에 결정적 역할을 하는 상부연수 복외측부에 존재하는 심맥관계 활동과 관련 있는 신경세포들에 대해 iontophoresis 법으로 투여한 신경흥분전달물질의 작용기전을 규명하고자 하였다. 이를 위해서 $\alpha$-chloralose로 마취한 고양이를 실험동물로 하여 연수의 복외측부에 multibarrel 전극을 삽입하여 심맥관계 활동과 관련 있는 신경세포의 활동을 세포외기록법으로 확인한 후 세포에 iontophoresis법으로 투여한 glutamate, GABA(\ulcorner-aminobutyric acid) 및 bicuculline의 효과를 관찰하여 다음과 같은 결과를 얻었다. 1) 자발적으로 활동전압을 보이지 않는 세포에서 glutamate를 10초 주기로 5초간 iontophoresis할 때 주기적인 세포활동을 기록할 수 있었고 이 활동은 동시에 가한 GABA에 의하여 억제되었다. 2) 자발적으로 활동하고 있는 세포들에 대하여 glutamate를 투여하였을 때 활동전압의 빈도가 증가하였고 GABA에 의해서 억제되었다. 3) GABA억제제인 bicuculline을 단독으로 투여시 활동전압 빈도의 증가는 뚜렷하지 않았으나 GABA와 동시 투여시에는 GABA의 억제작용을 차단하였다. 4) GABA의 작용은 RVLM(rostral ventrolateral medulla) 세포의 주기적 활동과 basal discharge 모두를 감소시켰으나 주기적 양상이 없어진 세포는 드물었다. 5) 말초에 가한 유해자극에 의하여 유발된 신경세포 활동이 GABA에 의하여 억제되었다. 이상의 결과로부터 $\alpha$-chloralose로 마취한 고양이에서 GABA는 RVLM에 존재하는 심맥관계 신경세포들에 대하여 억제적으로 작용하나 bicuculline의 투여후에도 이들 세포들의 주기적 활동이 유지되는 점으로 보아 RVLM세포의 자발적 흥분에 대하여 감압반사의 흥분이 기여하는 바가 크지는 않을 것으로 사료된다.

The medullospinal tract cells are known to play an important role in the control of the cardiovascular activities. To clarify the modes of action of the neurotransmitters on these cells, glutamate, GABA(${\gamma}$-aminobutyric acid) and bicuculline were applicated iontophoretically into the rostral ventrolateral medulla in adult cats anesthetised with ${\alpha}$-chloralose. Followings are the results obtained : 1. The spontaneous activities of the cardiac-related neurons in rostral ventrolateral medulla (RVLM) were increased by the glutamate and decreased by the GABA. 2. Bicuculline, an antagonist of GABA, alone didn't increase the frequency of the action potentials, but could reverse the cellular response to the GABA, simultaneously applicated. 3. GABA seemed to decrease the peak as well as the basal discharge of the neurons in RVLM, but hardly changed their periodicities. 4. The cellular responses of RVLM evoked by the peripheral nerve stimulation could be inhibited by the iontophoretically released GABA. In conclusion, GABA seemed to act as an inhibitory neurotransmitter on the cardiac- related neurons in RVLM of the cats anesthetized with ${\alpha}$-chloralose. But the maintenance of the periodicities of these cells after the application of bicuculline suggested that the afferent activity of the baroreceptor didn't play a key role in the spontaneous activities of the RVLM neurons.

키워드

참고문헌

  1. J Physiol v.229 Blood pressure effects obtained by drugs applied to the ventral surface of the brain stem Guertzenstein PG
  2. J Auto Nerv Sys v.17 Identification and properites of subretrofacial bulbospinal neurons: A descending cardiovascular pathway in the cat McAllen RM
  3. J Comp Neurol v.228 Rostral ventrolateral medulla: selective projections to the thoracic autonomic cell column from the region containing C1 adrenaline neurons Ross CA;Ruggiero DA;Joh TH;Park DH;Reis DJ
  4. J Auto Nerv Sys v.9 Direct pathway from cardiovascular neurons in the ventrolateral medulla to regions of the intermediolateral nucleus of the up-perthoracic cord: an anatomical and electrophysiological study in the cat Caverson MM;Ciriello J;Calaresu FR
  5. Brain Res Rev v.11 Function of the ventrolateral medulla in the control of circulation Ciriello J;Caverson MM;Polosa C
  6. Brain Res v.253 Inhibitory cardiovascular function of neurons in the caudal ventrolateral medulla of the rabbit relationship to the area containing AI noradrenergic cells Blessing WW;Reis DJ
  7. Brain Res v.321 Interdependence of rostral and caudal ventrolateral medullary areas in the control of blood pressure Willette RN;Punnen S;Krieger AJ;Sapru HN
  8. The Central Neural Organization of Cardiovascular Control Basis for the naturally occurring activity of rostral ventrolateral medullary sympathoexcitatory neurons Barman SM;Gebber GL;Ciriello J;Caverson MM;Polosa C
  9. Neurosci Letts v.203 Depressor pathway involved in somatosympathetic reflex in cats Goo YS;Kim SJ;Lim W;Kim J
  10. J Neurosci v.8 Reticulospinal vasomotor neurons of the rat rostral ventrolateral medulla: relationship to sympathetic nerve activity and the C1 adrenergic cell group Morrison SF;Milner TA;Reis DJ
  11. Am J Physiol v.264 Identification of baroreceptor reflex interneurons in the caudal ventrolateral medulla Jeske I;Morrison SF;Cravo SL;Reis DJ
  12. J Comp Neurol v.276 Evidence for direct projections from the nucleus of the solitary tract onto medullary adrenaline cells Hancock MB
  13. Am J Physiol v.258 Inhibition of rostral VLM by baroreceptor activation is relayed through caudal VLM Agarwal SK;Gelsema AJ;Calaresu FR
  14. J Physiol v.258 The location of cardiac vagal preganglionic motoneurones in the medulla of the cat McAllen RM;Spyer KM
  15. Am J Physiol v.239 Sympathetic nerve rhythm of brainstem origin Barman SM;Gebber GL
  16. Am J Physiol v.252 Arterial baroreceptor and vagus inputs to sympathoexcitatory neurons in rat medulla Sun MK;Guyenet PG
  17. Am J Physiol v.256 Neurons of rostral ventrolateral medulla mediate somatic pressor reflex Stornetta RL;Morrison SF;Ruggiero DA;Reis DJ
  18. J Neurosci v.12 Intracellular analysis in vivo of different barosensitive bulbospinal neurons in the rat rostral ventrolateral medulla Granata AR;Kitai ST
  19. Am J Physiol v.249 GABA-mediate baroreceptor inhibition of reticulospinal neurons Sun MK;Guyenet PG
  20. J Auto Nerv Sys v.22 Hypotensive effects of lesions of the rostral ventrolateral medulla in rats are anesthetic-dependent Cochrane KL;Buchholz RA;Hubbard JW;Keeton K;Nathan MA