Table 2. Effects of cannabinoid- and vanilloid-related drugs on defensive behavior when injected into the intradorsal periaqueductal gray region.
| Drug (dose) | Possible mechanism | Species | Animal model | Main effect | References |
|---|---|---|---|---|---|
| ACEA (0.01-5 pmol) | CB1/TRPV1 agonist | Rat | EPM | Anxiolytic | 59*,63 |
| EsES | Panicolytic | ||||
| AEA (0.5-50 pmol) | CB1/TRPV1 agonist | Rat | EPM, VCT | Anxiolytic | 59*,60,61 |
| CFC | ↓CER | ||||
| AM251 (10-100 pmol) | CB1 antagonist | Rat | EPM, VCT | No effect | 59,60,67 |
| AM404 (50 pmol) | AEA uptake/metabolism inhibitor | Rat | VCT | Anxiolytic | 60,61 |
| CFC | ↓CER | ||||
| Capsazepine (0.1-60 nmol) | TRPV1 antagonist | Rat | EPM, VCT | Anxiolytic | 63,64 |
| EsES | Panicolytic | ||||
| Capsaicin (0.01-1 nmol) | TRPV1 agonist | Rat | EsES | Anxiolytic | 69 |
| CBD (10-60 nmol) | 5-HT1A agonist | Rat | EPM, ETM | Anxiolytic | 67* |
| EsES | Panicolytic | ||||
| HU210 (0.25-12.9 nmol) | CB1 agonist | Rat | EsCS, EsUs | Antiaversive | 57,58 |
| SB366791 (10 nmol) | TRPV1 selective antagonist | Rat | EsES | Panicolytic | 63 |
| URB597 (0.01 nmol) | AEA metabolism inhibitor | Rat | VCT | Anxiolytic | 60 |
| WIN55,212-2 (3-30 pmol) | CB1/TRPV1 agonist | Rat | EPM | Anxiolytic | 68 |
Drugs: ACEA = arachidonoylchloroethanolamide; AEA = anandamide; CBD = cannabidiol. Mechanisms: CB1 = cannabinoid receptor type 1; TRPV1 = transient receptor potential vanilloid type-1 channel; 5-HT1A = 5-hydroxytryptamine-1A. Models: EPM = elevated plus-maze; EsES = escape induced by dPAG electrical stimulation; VCT = Vogel conflict test; CFC = contextual fear conditioning; ETM = elevated T-maze; EsCS = escape induced by dPAG chemical stimulation; EsUs: escape induced by ultrasound. Effects: CER = conditioned emotional response. *Indicates a bell-shaped dose-response curve.