Table 1.
Neuronal cell counts in sensory and sympathetic populations of wild type, trkC, and NT-3 mutant mice
| Wild type (5) | trkC −/− (5) | Reduction, % | |
| Sensory ganglia | |||
| Trigeminal | 50,646 ± 353 | 39,912 ± 638 | 21*** |
| Geniculate | 1,569 ± 132 | 1,419 ± 85 | 11 |
| Vestibular | 4,324 ± 106 | 3,668 ± 60 | 15*** |
| Cochlear | 8,761 ± 644 | 2,611 ± 162 | 70*** |
| Petrosal-nodose | 10,084 ± 353 | 8,659 ± 296 | 14*** |
| L5 dorsal root (3) | 7,157 ± 587 | 4,770 ± 337 | 33** |
| Sympathetic ganglion | |||
| Superior cervical (3) | 25,084 ± 2,140 | 25,956 ± 1,912 | 0 |
| Wild type (3) | NT 3 −/− (3) | Reduction, % | |
| Sensory ganglia | |||
| Trigeminal | 39,765 ± 1,334 | 14,808 ± 953 | 62*** |
| Geniculate | 1,465 ± 135 | 949 ± 85 | 35* |
| Vestibular | 4,110 ± 335 | 3,352 ± 325 | 19 |
| Cochlear | 7,905 ± 331 | 980 ± 270 | 87*** |
| Petrosal-nodose | 9,724 ± 1,118 | 6,396 ± 724 | 34** |
| L5 dorsal root | 7,107 ± 627 | 2,222 ± 173 | 69*** |
| Sympathetic ganglion | |||
| Superior cervical | 23,862 ± 1,550 | 13,578 ± 1,896 | 44*** |
Tissue sections of newborn (P0) wild type and mutant littermates were prepared as described. Neurons having a clear nucleus and nucleolus were counted in every sixth section, and the sum of counts was multiplied by 6. Values are not corrected and are expressed as mean number of neurons ± SEM. Differences were evaluated using a one-tailed Student’s test; *P < 0.01, **P < 0.02, ***P < 0.005. In parenthesis, the numbers of animals analyzed are indicated. Wild-type mice derived from intercrosses of heterozygous trkC or NT-3 mice showed a significant difference in neuronal counts of the trigeminal ganglion. We hypothesize that this is caused by a maternal effect of reduced circulating NT-3 in the pregnant NT-3 +/− mice.