Expression of substance P, neurokinin 1 receptors (NK1) and neurokinin 3 receptors in the developing mouse retina and in the retina of NK1 knockout mice.
To complete a series of studies on the expression of substance P and neurokinin receptors in mammalian retinas, we investigated the occurrence of these molecules in developing mouse retinas and in retinas of mice with genetic deletion of the neurokinin 1 receptor, the preferred substance P receptor. Using semi-quantitative reverse transcription-polymerase chain reaction, we measured detectable levels of the gamma isoform of preprotachykinin A (a substance P precursor) mRNA at postnatal day 4. Neurokinin 1 receptor and neurokinin 3 receptor mRNAs were also detected at postnatal day 4. While gamma preprotachykinin A and neurokinin 1 receptor mRNA levels significantly increased up to eye opening (postnatal day 11), neurokinin 3 receptor mRNA levels remained constant throughout development. Substance P, neurokinin 1 receptor and neurokinin 3 receptor immunoreactivities were present at postnatal day 5. Substance P was in amacrine cells, neurokinin 1 receptor in developing amacrine and bipolar cells and neurokinin 3 receptor in OFF-type cone bipolar cells. Interestingly, a transient increase in the density of neurokinin 1 receptor immunoreactive processes was observed at eye opening in lamina 3 of the inner plexiform layer, suggesting a role of substance P and neurokinin 1 receptor in this developmental phase. However, in neurokinin 1 receptor knockout retinas, besides a significant increase of the gamma preprotachykinin A mRNA levels, no major changes were detected: neurokinin 3 receptor mRNA levels as well as substance P and neurokinin 3 receptor immunostainings were similar to wild types. Together with previous studies, these observations indicate that there are major differences in neurokinin 1 receptor expression patterns among developing mammalian retinas. The observations in neurokinin 1 receptor knockout mice may not be applicable to rats or rabbits, and substance P and neurokinin 1 receptor may play different developmental roles in different species.
Catalani
E
E
Dipartimento di Scienze Ambientali, Università della Tuscia, Largo dell'Università snc, blocco D, 01100 Viterbo, Italy.
Dal Monte
M
M
Gangitano
C
C
Lucattelli
M
M
Fineschi
S
S
Bosco
L
L
Bagnoli
P
P
Casini
G
G
D000375:Aging; D000818:Animals; D001483:Base Sequence; D021983:Cyclophilins / Q000235:genetics; D017931:DNA Primers; D018507:Gene Expression Regulation, Developmental; D051379:Mice; D018345:Mice, Knockout; D019696:Peptidylprolyl Isomerase / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D018040:Receptors, Neurokinin-1 / Q000172:deficiency* / Q000235:genetics*; D018042:Receptors, Neurokinin-3 / Q000235:genetics*; D012160:Retina / Q000254:growth & development / Q000502:physiology*; D013373:Substance P / Q000235:genetics*
D017931:DNA Primers; D012333:RNA, Messenger; D018040:Receptors, Neurokinin-1; D018042:Receptors, Neurokinin-3; C081786:cyclophilin B; D013373:Substance P; D021983:Cyclophilins; D019696:Peptidylprolyl Isomerase