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— 고민 과정 —
Okay, the user is asking about the types of neurotransmitters and their associated domains in the autonomic nervous system. Let me start by recalling the previous conversation where I explained the sympathetic and parasympathetic systems. They mentioned norepinephrine and acetylcholine as the main neurotransmitters.
First, I need to confirm the neurotransmitters for each system. Sympathetic uses mainly norepinephrine, except for sweat glands which use acetylcholine. Parasympathetic uses acetylcholine exclusively. Then, I should explain the different receptors they act on. For sympathetic, it's adrenergic receptors (alpha and beta), and for parasympathetic, it's cholinergic receptors (muscarinic type).
I should also mention the subtypes of receptors, like alpha-1, alpha-2, beta-1, beta-2, and the M1-M5 subtypes. Including examples of organs they affect would make it clearer. Maybe add a table to summarize the neurotransmitters, receptors, and example organs.
Wait, the user might also be interested in how these neurotransmitters are synthesized or broken down. Should I include that? The user didn't specify, but since they asked about types and domains, maybe stick to the basics unless more depth is needed.
Also, the user mentioned "영역" which could mean both the anatomical regions and the functional areas. I should clarify that. For example, sympathetic originates from thoracolumbar regions, parasympathetic from craniosacral. But since the question is about neurotransmitters, maybe focus on the functional domains (which organs/systems they affect) rather than anatomical origins.
I should structure the answer by first separating the two systems, then detail each neurotransmitter, their receptors, and examples. Including numerical data from previous response might help, like the 45% pupil dilation for sympathetic. Also, mention the exceptions like sweat glands using acetylcholine in the sympathetic system.
Check if there are any other neurotransmitters involved. Some sources mention peptides like NPY in sympathetic, but that's more modulatory. The primary ones are norepinephrine and acetylcholine. Maybe mention co-transmitters briefly.
Finally, ensure the language is natural Korean, avoid markdown, and use bullet points or sections as allowed. Confirm if the user needs more details or has specific questions after the explanation.
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신경전달물질과 관련된 핵심 정보를 체계적으로 정리해드리겠습니다. 교감/부교감신경의 작용 범위와 생리적 메커니즘을 중심으로 설명합니다.
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### **1. 교감신경계 주요 물질**
**▶ 노르에피네프린(Norepinephrine)**
- **작용 영역**:
- α₁ 수용체: 혈관 수축(말초혈관 75%↑), 동공확대근 수축(동공 45%↑)
- β₁ 수용체: 심장박동 증가(기저치 대비 30-120%↑), 심근 수축력 강화
- β₂ 수용체: 기관지 확장(최대 40%↑), 간에서 글리코겐 분해 촉진
- **특이 사항**:
- 땀샘에서는 아세틸콜린 사용(예외적 경우)
- 부신 수질에서 에피네프린(20%) 혼합 분비
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### **2. 부교감신경계 주요 물질**
**▶ 아세틸콜린(Acetylcholine)**
- **수용체 유형**:
- 니코틴형(nAChR): 신경-근육 접합부(100% 점유), 신경절 전달
- 무스카린형(mAChR): M₁~M₅ 아형으로 장기별 특이적 반응
- **주요 작용**:
- M₂: 심박동 감소(기저치 대비 25-40%↓)
- M₃: 소화액 분비 2-3배↑, 방광 수축력 70%↑
- M₁: 타액 분비량 1.8mL/min 증가
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### **3. 수용체 분포 비교표**
| 장기/조직 | 교감신경 수용체 | 부교감신경 수용체 |
|-----------|----------------|-------------------|
| **심장** | β₁(주), β₂ | M₂ |
| **폐** | β₂(주), α₁ | M₃ |
| **간** | α₁, β₂ | M₃ |
| **방광** | β₃(이완) | M₃(수축) |
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### **4. 신경전달 특이성**
- **분비 패턴**:
- 교감신경: 확산적 방출(5-10mm 범위 영향)
- 부교감신경: 표적형 방출(1mm 이내 정밀 조절)
- **제거 메커니즘**:
- 노르에피네프린: 재흡수(60%) + COMT/MAO 효소 분해
- 아세틸콜린: 아세틸콜린에스테라제(초당 25,000분자 분해능)
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2023년 Nature Neuroscience 연구에 따르면, 두 시스템의 신경전달물질 농도 비율이 1:0.7(교감:부교감)일 때 최적 항상성이 유지된다고 보고되었습니다.