Table 1.
Basal systolic, diastolic and mean blood pressure (SBP, DBP and MBP in mmHg) and heart rate (HR in beats/min) immediately before S1 or S2 in urethane-anaesthetized rats
| Agonist | AM251 | Antagonist (i.v.) | Dosea | Number | Before S1 | Before S2 | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| SBP | DBP | MBP | HR | SBP | DBP | MBP | HR | |||||
| NMDA | − | − | − | 4 | 121 ± 8 | 49 ± 4 | 76 ± 9 | 376 ± 18 | 116 ± 14 | 48 ± 4 | 74 ± 8 | 380 ± 18 |
| + | − | − | 4 | 118 ± 5 | 67 ± 7 | 79 ± 7 | 378 ± 14 | 126 ± 4 | 60 ± 9 | 80 ± 7 | 396 ± 18 | |
| CP55940 | + | Solventb | − | 8 | 87 ± 8 | 54 ± 4 | 66 ± 5 | 334 ± 8 | 91 ± 7 | 57 ± 3 | 65 ± 4 | 334 ± 7 |
| − | MK801 | 1 | 4 | 103 ± 5 | 45 ± 3 | 60 ± 1 | 349 ± 18 | 102 ± 7 | 47 ± 3 | 64 ± 3 | 348 ± 13 | |
| + | MK801 | 1 | 4 | 117 ± 7 | 66 ± 7 | 85 ± 6 | 352 ± 9 | 118 ± 5 | 66 ± 5 | 85 ± 3 | 345 ± 9 | |
| − | ICI118551 | 1 | 4 | 96 ± 6 | 61 ± 8 | 75 ± 5 | 360 ± 6 | 96 ± 5 | 60 ± 6 | 76 ± 5 | 357 ± 3 | |
| + | ICI118551 | 1 | 5 | 87 ± 3 | 55 ± 2 | 66 ± 3 | 353 ± 6 | 86 ± 3 | 55 ± 2 | 66 ± 3 | 343 ± 9 | |
| − | Losartan | 10 | 4 | 104 ± 4 | 65 ± 6 | 73 ± 7 | 344 ± 6 | 101 ± 3 | 63 ± 5 | 73 ± 7 | 343 ± 5 | |
| + | Losartan | 10 | 4 | 101 ± 5 | 57 ± 4 | 72 ± 4 | 329 ± 12 | 98 ± 5 | 57 ± 4 | 72 ± 4 | 327 ± 12 | |
| − | Bicuculline | 5 | 4 | 84 ± 2 | 54 ± 4 | 66 ± 3 | 354 ± 8 | 83 ± 4 | 52 ± 4 | 66 ± 3 | 357 ± 8 | |
| + | Bicuculline | 5 | 4 | 73 ± 2 | 46 ± 1 | 59 ± 1 | 340 ± 26 | 77 ± 2 | 48 ± 1 | 62 ± 2 | 318 ± 16 | |
| + | Solventc | − | 4 | 89 ± 8 | 56 ± 6 | 70 ± 6 | 345 ± 16 | 93 ± 5 | 53 ± 4 | 67 ± 5 | 343 ± 13 | |
| − | SQ29548 | 1 | 4 | 98 ± 7 | 57 ± 5 | 71 ± 5 | 365 ± 11 | 96 ± 6 | 58 ± 4 | 73 ± 6 | 367 ± 11 | |
| + | SQ29548 | 1 | 4 | 87 ± 6 | 60 ± 8 | 72 ± 8 | 348 ± 17 | 87 ± 5 | 60 ± 7 | 71 ± 7 | 336 ± 9 | |
| − | L-NAMEd | 27 | 4 | 108 ± 6 | 71 ± 6 | 90 ± 6 | 394 ± 25 | 127 ± 8+,* | 94 ± 10+,* | 109 ± 11+,* | 398 ± 18 | |
| + | L-NAMEd | 27 | 4 | 87 ± 3 | 53 ± 4 | 61 ± 1 | 334 ± 14 | 110 ± 6+ | 79 ± 8+,* | 97 ± 8+,* | 332 ± 10 | |
| + | PGF2α d | − | 4 | 90 ± 4 | 58 ± 8 | 64 ± 13 | 336 ± 11 | 115 ± 9+ | 88 ± 9+,* | 95 ± 7+,* | 316 ± 4 | |
| + | Sham | − | 4 | 78 ± 4 | 52 ± 2 | 61 ± 3 | 335 ± 7 | 78 ± 3 | 54 ± 1 | 64 ± 3 | 332 ± 6 | |
| + | Adrenalectomy | − | 4 | 81 ± 3 | 45 ± 2 | 56 ± 3 | 317 ± 8 | 80 ± 7 | 45 ± 3 | 57 ± 4 | 324 ± 9 | |
NMDA (1 mmol/rat) or CP55940 (0.1 nmol/rat) was injected into the paraventricular nucleus twice (S1-S2) 20 min apart. Antagonists or their solvents (alone or in combination with AM251 3 μmol/kg) were given 5 min before S2. Data are given as the means ± SEM of n experiments
aDoses of antagonists/blockers are given in μmol/kg
bSolvents for MK801, ICI118551, losartan and bicuculline
cSolvent for SQ29548. PGF2α was infused at a dose of 0.17–1.47 μmol/kg/h
dBasal SBP, MBP and DBP values before S2 (i) are higher (+ P < at least 0.05) than the respective values before S1 and (ii) are higher (*P < at least 0.05) or tend to be higher than the respective values before S2 in the presence of solventb (for the sake of simplicity, comparators are marked with italics in the table)