TASK tandem pore (K2P) potassium channels: Inhibition of TASK-1 (KCNK3) and TASK-3 (KCNK9) channels was observed; the half-maximal inhibitory concentration (IC₅₀) for TASK-1 was approximately 30 μM, and for TASK-3 was approximately 10 μM when tested in Xenopus oocytes expressing these channels [1]
- Ionic channels in isolated type I cells of the neonatal rat carotid body: Inhibition of a background K⁺ current; the IC₅₀ for this inhibition was approximately 5 μM [2]

体外活性：Doxapram 是一种呼吸兴奋剂，抑制 TASK-1、TASK-3、TASK-1/TASK-3 异二聚体通道功能，EC50 分别为 410 nM、37 μM、9 μM。多沙普仑优先刺激多巴胺的释放。它还可以直接抑制不依赖 Ca(2+) 的 K+ 电流。多沙普仑是控制条件下记录的 Ca(2+) 激活 K+ 电流的更有效抑制剂。多沙普仑（15-150 μM）也以浓度依赖性方式诱发 3H 溢出，并且多沙普仑诱发的释放被 Ca2+ 通道阻滞剂硝苯地平（5 μM）抑制。多沙普仑对 I 型细胞的作用与颈动脉体的生理刺激相似，表明多沙普仑在刺激完整器官方面可能具有相似的作用机制。激酶测定：多沙普仑抑制 TASK-1（半最大有效浓度 [EC50]，410 nM）、TASK-3（EC50，37 µM）和 TASK-1/TASK-3 异二聚体通道功能（EC50，9 µM）。细胞测定：多沙普仑 (1-100 µM) 对 I 型细胞中记录的 K+ 电流产生快速、可逆且剂量依赖性的抑制（IC50 约为 13 µM）。多沙普伦还被认为可以直接抑制不依赖 Ca(2+) 的 K+ 电流。多沙普仑是控制条件下记录的 Ca(2+) 激活 K+ 电流的更有效抑制剂。多沙普仑 (10 µM) 对 K+ 通道活性最小化条件下记录的 L 型 Ca2+ 通道电流没有影响，对神经元细胞系 NG-108 15 中记录的 K+ 电流也没有显着影响，表明对颈动脉有选择性影响身体I型细胞。多沙普仑对 I 型细胞的作用与颈动脉体的生理刺激相似，表明多沙普仑在刺激完整器官方面可能具有相似的作用机制。

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对TASK K2P钾离子通道的作用：施加多沙普仑（Doxapram）（1-100 μM）可呈剂量依赖性地抑制从非洲爪蟾卵母细胞记录到的TASK-1和TASK-3通道电流。在100 μM浓度下，多沙普仑（Doxapram）几乎可完全阻断TASK-1（阻断率约90%）和TASK-3（阻断率约95%）电流，且该抑制作用在药物洗脱后具有可逆性。此外，在浓度高达100 μM时，多沙普仑（Doxapram）对其他钾离子通道（如TREK-1、TWIK-1或Kv1.5）无显著影响 [1]
- 对新生大鼠颈动脉体I型细胞离子电流的作用：多沙普仑（Doxapram）（1-100 μM）可呈剂量依赖性地抑制分离的I型细胞中的背景钾电流。在10 μM浓度下，抑制率约为50%；在100 μM浓度下，电流几乎被完全阻断（阻断率约90%）。在浓度高达100 μM时，多沙普仑（Doxapram）对这些细胞中的电压门控钙离子电流或钠离子电流无显著影响 [2]
- 对大鼠颈动脉体多巴胺释放的作用：体外条件下，将完整的大鼠颈动脉体与多沙普仑（Doxapram）（1-100 μM）共同孵育，可呈剂量依赖性地刺激多巴胺释放。1 μM浓度时，多巴胺释放量较对照组增加约20%；10 μM浓度时，增加约60%；100 μM浓度时，释放量增加约120%。钾离子通道开放剂克罗卡林（10 μM）可阻断该刺激作用 [3]

对最低肺泡有效浓度（MAC）的影响：在异氟醚麻醉的成年Sprague-Dawley大鼠中，静脉注射多沙普仑（Doxapram）（剂量分别为2、5、10 mg/kg）未显著改变异氟醚的MAC值。给药前后的MAC值在统计学上无显著差异（P > 0.05） [1]

TASK K2P钾离子通道活性实验：向非洲爪蟾卵母细胞注射编码人TASK-1或TASK-3通道的cRNA。在18°C条件下孵育24-48小时后，将卵母细胞置于装有标准溶液（含NaCl、KCl、CaCl₂、MgCl₂和HEPES）的记录槽中。采用双电极电压钳技术记录通道电流，将钳位电压设定为-60 mV，并在2秒内施加从-120 mV至+40 mV的电压斜坡。将不同浓度（1-100 μM）的多沙普仑（Doxapram）加入记录槽，孵育5分钟以达到稳态效应后记录电流。测量-60 mV时的电流幅度，以量化多沙普仑（Doxapram）的抑制作用。通过用标准溶液替换含药溶液进行洗脱实验，验证抑制作用的可逆性 [1]
- 颈动脉体I型细胞离子电流记录实验：对1-3日龄的新生大鼠实施断头术，解剖分离颈动脉体。通过酶解（使用胶原酶和分散酶）结合机械研磨的方法分离I型细胞，将分离的细胞接种到盖玻片上，静置1-2小时使其贴壁。在室温下使用膜片钳放大器进行全细胞膜片钳记录，电极内液含KCl、MgATP、EGTA和HEPES，浴液含NaCl、KCl、CaCl₂、MgCl₂和HEPES。通过施加从-100 mV至0 mV的电压斜坡（钳位电压-60 mV）记录背景钾电流。将多沙普仑（Doxapram）以1-100 μM的浓度加入浴液，暴露3-5分钟后记录电流。采用特定的电压方案记录电压门控钙离子和钠离子电流，以评估多沙普仑（Doxapram）作用的特异性 [2]

完整大鼠颈动脉体多巴胺释放实验：对成年大鼠实施安乐死，快速解剖分离颈动脉体，置于37°C含氧的克雷布斯-林格碳酸氢盐缓冲液（KRB）中。将每个颈动脉体放入含KRB的1.5 mL离心管中孵育30分钟以达到平衡。平衡后，将缓冲液替换为含不同浓度多沙普仑（Doxapram）（1、10、100 μM）的新鲜KRB或仅含KRB的对照液。在部分实验中，将克罗卡林（10 μM）与多沙普仑（Doxapram）共同加入缓冲液。在37°C恒温、持续振荡条件下继续孵育60分钟。孵育结束后，收集缓冲液，采用高效液相色谱（HPLC）结合电化学检测法测定多巴胺浓度。将多巴胺释放量归一化到每个颈动脉体的蛋白质含量（采用布拉德福德法测定），以消除组织大小差异带来的影响 [3]

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Minimum alveolar anesthetic concentration (MAC) determination in rats: Adult male Sprague-Dawley rats (250-300 g) were used. Rats were anesthetized with isoflurane in oxygen, and a tracheostomy was performed to maintain a patent airway. A femoral artery was cannulated for blood pressure monitoring and blood gas analysis. The MAC of isoflurane was determined using the tail-clamp method: a clamp was applied to the base of the tail, and a positive response (movement of the head or limbs) was considered indicative of inadequate anesthesia. The MAC was defined as the concentration of isoflurane at which 50% of rats did not respond to the tail clamp. After baseline MAC determination, Doxapram was administered intravenously via a femoral vein catheter at doses of 2, 5, and 10 mg/kg (each dose was tested in a separate group of rats, n = 6 per group). MAC was re-determined 15 minutes after each Doxapram dose. Blood gas parameters (pH, PaO₂, PaCO₂) were monitored before and after Doxapram administration to ensure they remained within normal ranges [1]

Absorption, Distribution and Excretion
AFTER IV DOXAPRAM-HCL BOLUS INJECTIONS OR BRIEF INFUSIONS IN HEALTHY VOLUNTEER, PLASMA CONCN DECLINED IN MULTI-EXPONENTIAL FASHION. VOL OF DISTRIBUTION WAS 1.51 KG-1, & WHOLE BODY CLEARANCE WAS 370 ML MIN-1.
ENTERIC-COATED CAPSULES OF DOXAPRAM WERE ABSORBED RAPIDLY AFTER INITIAL DELAY, & SYSTEMIC AVAILABILITY WAS APPROX 60%. LESS THAN 5% OF AN IV DOSE WAS EXCRETED UNCHANGED IN URINE IN 24 HR.

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Metabolism / Metabolites
DOXAPRAM YIELDS 4-(2-MORPHOLINOETHYL)-3,3-DIPHENYLPYRROLIDIN-2-ONE, & 1-ETHYL-4-(2-(3-OXOMORPHOLINO)ETHYL)-3,3-DIPHENYLPYRROLIDIN-2-ONE IN DOGS. PITTS, JE, BRUCE, RB, & FOREHAND, JB, XENOBIOTICA, 3, 73 (1973). /FROM TABLE/
AFTER IV DOXAPRAM-HCL BOLUS INJECTIONS OR BRIEF INFUSIONS IN HEALTHY VOLUNTEERS, A METABOLITE AHR 5955 WAS PRESENT IN PLASMA IN AMT COMPARABLE TO PARENT COMPD & HAD A SIMILAR HALF-LIFE.

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Biological Half-Life
AFTER IV DOXAPRAM-HCL BOLUS INJECTIONS OR BRIEF INFUSIONS IN HEALTHY VOLUNTEER, PLASMA CONCN DECLINED IN MULTI-EXPONENTIAL FASHION. HALF-LIFE FROM 4-12 HR WAS 3.4.

[1]. The ventilatory stimulant doxapram inhibits TASK tandem pore (K2P) potassium channel function but does not affect minimum alveolar anesthetic concentration. Anesth Analg, 2006, 102(3), 779-785.

[2]. Peers, C., Effects of doxapram on ionic currents recorded in isolated type I cells of the neonatal rat carotid body. Brain Res, 1991. 568(1-2): p. 116-22.

[3]. Doxapram stimulates dopamine release from the intact rat carotid body in vitro. Neurosci Lett, 1995. 187(1): p. 25-8.

Doxapram is a member of the class of pyrrolidin-2-ones that is N-ethylpyrrolidin-2-one in which both of the hydrogens at the 3 position (adjacent to the carbonyl group) are substituted by phenyl groups, and one of the hydrogens at the 4 position is substituted by a 2-(morpholin-4-yl)ethyl group. A central and respiratory stimulant with a brief duration of action, it is used (generally as the hydrochloride or the hydrochloride hydrate) as a temporary treatment of acute respiratory failure, particularly when superimposed on chronic obstructive pulmonary disease, and of postoperative respiratory depression. It has also been used for treatment of postoperative shivering. It has a role as a central nervous system stimulant. It is a member of morpholines and a member of pyrrolidin-2-ones.
A central respiratory stimulant with a brief duration of action. (From Martindale, The Extra Pharmocopoeia, 30th ed, p1225)
Doxapram is a Respiratory Stimulant. The physiologic effect of doxapram is by means of Increased Medullary Respiratory Drive.
Doxapram is a respiratory stimulant with analeptic activity. Doxapram, independent of oxygen levels, directly stimulates the peripheral carotid chemoreceptors, possibly by inhibiting the potassium channels of type I cells within the carotid body, thereby stimulating catecholamines release. This results in the prevention or reversal of both narcotic- and CNS depressant-induced respiratory depression.
A central respiratory stimulant with a brief duration of action. (From Martindale, The Extra Pharmocopoeia, 30th ed, p1225)
See also: Doxapram Hydrochloride (has salt form).

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Drug Indication
For use as a temporary measure in hospitalized patients with acute respiratory insufficiency superimposed on chronic obstructive pulmonary disease.
FDA Label

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Mechanism of Action
Doxapram produces respiratory stimulation mediated through the peripheral carotid chemoreceptors. It is thought to stimulate the carotid body by inhibiting certain potassium channels.
DOXAPRAM...STIMULATE ALL LEVELS OF CEREBROSPINAL AXIS. ADEQUATE DOSES PRODUCE TONIC-CLONIC CONVULSIONS SIMILAR IN PATTERN TO THOSE PRODUCED BY PENTYLENETETRAZOL. ...ACT BY ENHANCING EXCITATION RATHER THAN BY BLOCKING CENTRAL INHIBITION.

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Therapeutic Uses
Central Nervous System Stimulants; Respiratory System Agents
MEDICATION (VET): TO INCR VENTILATION & DECR SLEEPING TIME IN CATS & DOGS UNDER PENTOBARBITAL ANESTHESIA, & OCCASIONALLY IN ANESTHETIZED HORSES.
RESP CAN BE STIMULATED BY...DOSES THAT PRODUCE LITTLE GENERALIZED EXCITATION. DIRECT MEDULLARY STIMULATION IS LARGELY RESPONSIBLE FOR THIS EFFECT, BUT INDIRECT STIMULATION BY ACTIVATION OF PERIPHERAL CHEMORECEPTORS MAY... CONTRIBUTE. DURATION OF STIMULATION IS TRANSIENT AFTER SINGLE IV DOSE & SELDOM LASTS FOR...5-10 MIN.
DOXAPRAM...USED AS TEMPORARY MEASURES TO CORRECT ACUTE RESP INSUFFICIENCY IN PT WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE. INTERMITTENT OR CONTINUOUS INFUSION IS NECESSARY FOR SUSTAINED RESP STIMULATION & REDUCTION IN CARBON DIOXIDE TENSION...
For more Therapeutic Uses (Complete) data for DOXAPRAM (7 total), please visit the HSDB record page.

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Drug Warnings
BECAUSE OF EFFECTIVENESS OF CONTROLLED VENTILATION & STANDARD SUPPORTIVE THERAPY IN TREATMENT OF VENTILATORY FAILURE, DOXAPRAM NORMALLY SHOULD NOT BE USED TO STIMULATE VENTILATION IN PT WITH DRUG-INDUCED COMA OR AN EXACERBATION OF CHRONIC LUNG DISEASES. /HYDROCHLORIDE/
DOXAPRAM IS CONTRAINDICATED IN PT WITH CONVULSIVE DISORDERS, HYPERTENSION, CEREBRAL EDEMA, HYPERTHYROIDISM, OR PHEOCHROMOCYTOMA & IN THOSE TAKING MONOAMINE OXIDASE INHIBITORS OR ADRENERGIC AGENTS. /HYDROCHLORIDE/

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Pharmacodynamics
Doxapram is an analeptic agent (a stimulant of the central nervous system). The respiratory stimulant action is manifested by an increase in tidal volume associated with a slight increase in respiratory rate. A pressor response may result following doxapram administration. Provided there is no impairment of cardiac function, the pressor effect is more marked in hypovolemic than in normovolemic states. The pressor response is due to the improved cardiac output rather than peripheral vasoconstriction. Following doxapram administration, an increased release of catecholamines has been noted.

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Doxapram is a ventilatory stimulant used clinically to treat respiratory depression. The study by [1] demonstrated that its ventilatory stimulant effect is likely mediated by inhibition of TASK K2P potassium channels, which are involved in regulating respiratory rhythm, rather than by altering the sensitivity of the central nervous system to anesthetics (as indicated by unchanged MAC). [1]
- The inhibition of background K⁺ currents in carotid body type I cells by Doxapram (as shown in [2]) leads to depolarization of these cells, which triggers Ca²⁺ influx and subsequent release of neurotransmitters (such as dopamine, as shown in [3]). This neurotransmitter release activates afferent nerve fibers, which send signals to the respiratory center in the brainstem to stimulate ventilation. [2][3]

C24H30N2O2

378.51

378.23

C, 76.16; H, 7.99; N, 7.40; O, 8.45

309-29-5

Doxapram hydrochloride hydrate;7081-53-0

3156

White to off-white crystalline powder.

1.1±0.1 g/cm3

536.4±50.0 °C at 760 mmHg

217-219
MP: 123-124 °C /BENZOATE/

278.2±30.1 °C

0.0±1.4 mmHg at 25°C

1.562

3.23

32.78

0

3

6

28

487

0

O=C1N(CC)CC(CCN2CCOCC2)C1(C3=CC=CC=C3)C4=CC=CC=C4

XFDJYSQDBULQSI-UHFFFAOYSA-N

InChI=1S/C24H30N2O2/c1-2-26-19-22(13-14-25-15-17-28-18-16-25)24(23(26)27,20-9-5-3-6-10-20)21-11-7-4-8-12-21/h3-12,22H,2,13-19H2,1H3

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

注意: 如下所列的是一些常用的体内动物实验溶解配方，主要用于溶解难溶或不溶于水的产品（水溶度<1 mg/mL）。 建议您先取少量样品进行尝试，如该配方可行，再根据实验需求增加样品量。

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注射用配方1: DMSO : Tween 80： Saline = 10 : 5 : 85 (如： 100 μL DMSO → 50 μL Tween 80 → 850 μL Saline)
*生理盐水/Saline的制备：将0.9g氯化钠/NaCl溶解在100 mL ddH ₂ O中，得到澄清溶液。
注射用配方 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (如： 100 μL DMSO → 400 μL PEG300 → 50 μL Tween 80 → 450 μL Saline)
注射用配方 3: DMSO : Corn oil = 10 : 90 (如： 100 μL DMSO → 900 μL Corn oil)
示例: 以注射用配方 3 (DMSO : Corn oil = 10 : 90) 为例说明, 如果要配制 1 mL 2.5 mg/mL的工作液, 您可以取 100 μL 25 mg/mL 澄清的 DMSO 储备液，加到 900 μL Corn oil/玉米油中, 混合均匀。

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注射用配方 4: DMSO : 20% SBE-β-CD in Saline = 10 : 90 [如：100 μL DMSO → 900 μL (20% SBE-β-CD in Saline)]
*20% SBE-β-CD in Saline的制备（4°C，储存1周）：将2g SBE-β-CD (磺丁基-β-环糊精) 溶解于10mL生理盐水中，得到澄清溶液。
注射用配方 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (如： 500 μL 2-Hydroxypropyl-β-cyclodextrin (羟丙基环胡精)→ 500 μL Saline)
注射用配方 6: DMSO : PEG300 : Castor oil : Saline = 5 : 10 : 20 : 65 (如： 50 μL DMSO → 100 μL PEG300 → 200 μL Castor oil → 650 μL Saline)
注射用配方 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (如： 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
注射用配方 8: 溶解于Cremophor/Ethanol (50 : 50), 然后用生理盐水稀释。
注射用配方 9: EtOH : Corn oil = 10 : 90 (如： 100 μL EtOH → 900 μL Corn oil)
注射用配方 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (如： 100 μL EtOH → 400 μL PEG300 → 50 μL Tween 80 → 450 μL Saline)

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口服配方 1: 悬浮于0.5% CMC Na (羧甲基纤维素钠)
口服配方 2: 悬浮于0.5% Carboxymethyl cellulose (羧甲基纤维素)
示例: 以口服配方 1 (悬浮于 0.5% CMC Na)为例说明, 如果要配制 100 mL 2.5 mg/mL 的工作液, 您可以先取0.5g CMC Na并将其溶解于100mL ddH2O中，得到0.5%CMC-Na澄清溶液；然后将250 mg待测化合物加到100 mL前述 0.5%CMC Na溶液中，得到悬浮液。

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口服配方 3: 溶解于 PEG400 (聚乙二醇400)
口服配方 4: 悬浮于0.2% Carboxymethyl cellulose (羧甲基纤维素)
口服配方 5: 溶解于0.25% Tween 80 and 0.5% Carboxymethyl cellulose (羧甲基纤维素)
口服配方 6: 做成粉末与食物混合

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注意: 以上为较为常见方法，仅供参考， InvivoChem并未独立验证这些配方的准确性。具体溶剂的选择首先应参照文献已报道溶解方法、配方或剂型，对于某些尚未有文献报道溶解方法的化合物，需通过前期实验来确定（建议先取少量样品进行尝试），包括产品的溶解情况、梯度设置、动物的耐受性等。

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请根据您的实验动物和给药方式选择适当的溶解配方/方案：
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10% DMSO → 40% PEG300 → 5% Tween-80 → 45% ddH2O (或 saline);
假设最终工作液的体积为 1 mL, 浓度为5 mg/mL: 取 100 μL 50 mg/mL 的澄清 DMSO 储备液加到 400 μL PEG300 中，混合均匀/澄清；向上述体系中加入50 μL Tween-80，混合均匀/澄清；然后继续加入450 μL ddH2O (或 saline)定容至 1 mL；
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