Dopamine D1 receptor

In D1HEK293 cells, the full D1 receptor agonist SKF-81297 evoked a robust dose-dependent increase in Ca(2+)(i) following 'priming' of endogenous G(q/11)-coupled muscarinic or purinergic receptors. The effect of SKF-81297 could be mimicked by forskolin or 8-Br-cAMP. Further, cholera toxin and the cAMP-dependent protein kinase (PKA) inhibitors, KT5720 and H89, as well as thapsigargin abrogated the D1 receptor evoked Ca(2+) transients. Removal of the priming agonist and treatment with the phospholipase C inhibitor U73122 also blocked the SKF-81297-evoked responses. D1R agonist did not stimulate IP(3) production, but pretreatment of cells with the D1R agonist potentiated G(q)-linked receptor agonist mobilization of intracellular Ca(2+) stores. In neurons,SKF-81297 and SKF83959, a partial D1 receptor agonist, promoted Ca(2+) oscillations in response to G(q/11)-coupled metabotropic glutamate receptor (mGluR) stimulation. The effects of both D1R agonists on the mGluR-evoked Ca(2+) responses were PKA dependent. Altogether the data suggest that dopamine D1R activation and ensuing cAMP production dynamically regulates the efficiency and timing of IP(3)-mediated intracellular Ca(2+) store mobilization. [3]

In MPTP-lesioned monkeys, SKF-81297 (0.05-0.3 mg/kg, intramuscular injection, once) promotes locomotor activity[1]. The alleged selective, high efficacy dopamine D1 receptor agonist, SKF-81297 (0.05-0.3 mg/kg i.m.), induced rotational behaviour away from the lesion and stimulated use of the dominant right hand in unilaterally (left side) 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned rhesus monkeys (Macaca mulatta). The effects of SKF-81297 were completely blocked by the dopamine D1 receptor antagonist, SCH 23390 (0.05 mg/kg), but not by the dopamine D2 receptor antagonist, remoxipride (1 mg/kg), and were similar to those induced by the selective dopamine D2 agonist, LY 171555 (0.01 mg/kg). These results suggest a functional stimulatory role for the dopamine D1 receptor on motor behaviour in a non-human primate model of Parkinson's disease when stimulated with a high efficacy selective dopamine D1 receptor agonist. [1]

---

Deficits in prefrontal cortex (PFC) GABAergic neurotransmission are linked to cognitive impairments seen in schizophrenia and other disorders, and pharmacological reduction of PFC GABAA transmission disrupts processes including working and spatial memory. This provides an opportunity to examine whether compounds capable of neutralizing GABAergic dysfunction may ameliorate these cognitive deficits. PFC dopamine (DA) D1 receptor activation enhances GABA transmission, raising the possibly that direct or indirect agonists of DA D1 receptors would be effective in reversing working memory and other forms of cognitive deficits. To test this, male rats were pre-treated with two drugs that augment PFC D1 signalling before PFC infusion of the GABAA antagonist, bicuculline (50 ng) and assessment of spatial working and reference memory function. A moderate dose of the full D1 agonist SKF-81297 (0.1 mg/kg) completely reversed PFC GABA hypofunction-induced working memory deficits assessed in an delayed-response task, whereas lower and higher doses (0.05 and 0.3 mg/kg respectively) were associated with mild improvements or deleterious effects. Treatment with the tetrahydroprotoberberine d-govadine (0.5 or 1.0 mg/kg), a synthetic compound known to enhance DA release selectively in the PFC, also significantly improved delayed-response working memory function induced by PFC GABAA antagonism. Furthermore, administration of the optimal dose of both drugs led to a partial rescue of PFC GABA hypofunction-induced reference and short-term spatial memory impairments assessed on a radial maze task. These findings suggest that modulation of PFC DA signalling via actions on the DA D1 receptor represents a promising therapeutic strategy for working memory and other cognitive impairments observed in psychiatric disorders, including those with causes that extend beyond DA dysfunction. [2]

Animal/Disease Models: Four male rhesus monkeys (Macaca mulatta, 7.0-11.3 kg)[1]
Doses: 0.05-0.3 mg/kg
Route of Administration: intramuscular (im) injection, once
Experimental Results: Dramatically increased rotational behavior and right-sided hand use in unilateral MPTP-lesioned rhesus monkeys.

---

Drugs, microinfusion procedures and experimental design [2]
Fig. 1 shows a timeline and details of the experimental design. Once a rat achieved criterion performance on a respective task, it received the first of four drug test days that entailed i.p. injection of a drug/vehicle and intra-PFC infusions of the GABAA receptor antagonist bicuculline methbromide (BIC; 50 ng in 0.5 μl) or saline vehicle, using procedures described previously (Auger and Floresco, 2015, Auger and Floresco, 2017). The drugs and doses used for i.p. treatment were the D1 receptor agonist SKF-81297 (SKF) (0.05, 0.1 and 0.3 mg/kg, i.p.) or d-Gov (0.5 and 1.0 mg/kg, i.p.), both of which were dissolved in saline. The four drug test conditions were (I) saline (SAL) i.p. injection-PFC SAL infusion, (“control treatment”), (II) SAL i.p.- PFC BIC infusion, (III) drug i.p. injection-PFC SAL infusion, (IV) drug i.p. injection- PFC BIC infusion. Separate groups of rats were used for each dose of the i.p.-administered drug to minimize the number of intracranial BIC infusions each animal would receive, meaning that each animal within a particular group received the same drug and dosage on both i.p. drug test days. The order of treatments was counter-balanced across animals. Animals were re-trained between test sessions until they re-achieved criterion performance for at least 2 consecutive days, at which point they received the next treatment day. The doses of SKF (Nikiforuk, 2012) and d-Gov (Lapish et al., 2012, Lapish et al., 2014) were selected from previous studies demonstrating improvements in cognition, and we have shown that the 50 ng dose of BIC impairs performance on these tasks without inducing seizures or other non-specific behavioral abnormalities (Auger and Floresco, 2015, Auger and Floresco, 2017, Auger et al., 2017, Auger et al., 2019, Enomoto et al., 2011). For the radial maze experiments, we tested the effects of a single dose of SFK and d-Gov that was shown to be most effective in the DNMTP experiments.

[1]. The selective dopamine D1 receptor agonist, SKF 81297, stimulates motor behaviour of MPTP-lesioned monkeys. Eur J Pharmacol. 1993 Apr 22;235(1):143-7.

[2]. Amelioration of cognitive impairments induced by GABA hypofunction in the male rat prefrontal cortex by direct and indirect dopamine D1 agonists SKF-81297 and d-Govadine. Neuropharmacology. 2020 Jan 1;162:107844.

[3]. A crucial role for cAMP and protein kinase A in D1 dopamine receptor regulated intracellular calcium transients. Neurosignals. 2008;16(2-3):112-23.

9-chloro-5-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine-7,8-diol is a benzazepine.

---

D1-like dopamine receptors stimulate Ca(2+) transients in neurons but the effector coupling and signaling mechanisms underlying these responses have not been elucidated. Here we investigated potential mechanisms using both HEK 293 cells that stably express D1 receptors (D1HEK293) and hippocampal neurons in culture. [3]
The present data highlight the therapeutic potential of d-Gov and other D1 agonists for treatment of cognitive impairment in schizophrenia and other psychiatric disorders. In particular, the findings indicate that modulation of mesocortical DA transmission via D1 receptor activation may be viable approach for mitigating cognitive deficits that originate from pathophysiological alterations that extend beyond changes in DA function, such as deficient GABAergic transmission. Therefore, it will be of considerable interest to investigate whether these compounds have utility in reversing the effects of other relevant neural alterations, particularly on other domains of cognition or behavior relevant to positive and negative symptomatology of schizophrenia.[3]

C16H16CLNO2.HBR

370.67

369.01312

C, 66.32; H, 5.57; Cl, 12.23; N, 4.83; O, 11.04

253446-15-0

Typically exists as solids at room temperature

C1=CC=C(C=C1)[C@H]2CNCCC3=C(C(=C(C=C32)O)O)Cl.Br

(R)-SKF-81297; 71636-61-8; (R)-SKF81297; Skf-81297; SKF 81297; SK&F 81297; 6-Chloro-2,3,4,5-tetrahydro-1-phenyl-1H-3-benzazepine-7,8-diol; SKF81297; 1H-3-Benzazepine-7,8-diol,6-chloro-2,3,4,5-tetrahydro-1-phenyl-; 9-chloro-5-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine-7,8-diol;

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)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

---

Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

View More

Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

---

Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

View More

Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

---

Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

---

 (Please use freshly prepared in vivo formulations for optimal results.)