The appearance of NPY and VIP in sympathetic neuroblasts and subsequent alterations in their expression

Abstract

Mature sympathetic neurons contain one or more neuropeptides in addition to a classical neurotransmitter. We compared the development of two peptides, neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP), in rat superior cervical (SCG) and stellate ganglia. NPY immunoreactivity (-IR) was first detected at embryonic day (E) 12.5. It was of similar immunofluorescence intensity in almost all tyrosine hydroxylase (TH)-IR cells. In contrast, VIP-IR, of variable fluorescence intensity, appeared at E14.5 in a subset of TH-IR cells in the stellate ganglion but not in SCG. Both peptides were present in bromodeoxyuridine-labeled neuronal precursors as well as neurons. The intensity of NPY immunofluorescence increased until E16.5. Subsequently, while it continued to increase in some neurons, the intensity decreased in others so that at birth approximately 55% of SCG and stellate neurons were NPY-IR. Developmental changes in NPY concentration, determined by radioimmunoassay, were similar in both ganglia, increasing between E14.5 and E16.5 and then decreasing 60% between E16.5 and birth. VIP expression differed from that of NPY. The proportion of VIP-IR cells began to decrease the day after VIP-IR was first detected. Although VIP-IR was present in one-third of E14.5 TH-IR stellate cells, at birth only 2% were VIP-IR. VIP-IR, measured by radioimmunoassay, was uniformly severalfold more concentrated in the stellate than SCG, and its concentration decreased throughout embryonic development, 40% between E14.5 and E16.5 and 95% by birth. In situ hybridization revealed detectable mRNA for both NPY and VIP at E14.5 in stellate ganglion and mRNA for NPY, but not VIP, in SCG. Initially, ganglionic neuropeptide mRNA appeared uniformly distributed but became heterogeneous. Our data indicate that features of the diverse peptidergic phenotypes expressed by sympathetic neurons are present when peptides are first detected while others arise subsequently. The final acquisition of peptidergic phenotypic diversity is complex, entailing both early induction in many cells and subsequent restriction to specific subpopulations.

Maternal vasoactive intestinal peptide and the regulation of embryonic growth in the rodent.

“…The fall of VIP in maternal serum is also closely followed by the appearance of VIP mRNA in fetal peripheral tissues (14,27), including the peripheral nervous system where VIP is seen to peak in the stellate ganglia at E14.5 (28), and significant amounts of VIP were also detected in the superior cervical ganglia (10). The VIP synthesized by peripheral fetal tissues during the last third of pregnancy may provide a source of VIP to act on the abundant VIP binding sites seen throughout the CNS during this time (14).…”

Developmental expression of the high affinity choline transporter in cholinergic sympathetic neurons

“…The anti-CHT antiserum used for staining mouse tissue was generated in rabbits against a C-terminal peptide (DSSPEGSGTEDNLQ) corresponding to rodent CHT with an N-terminal cysteine for conjugation to keyhole limpet hemocyanin. The VIP antiserum was generated in guinea pig (Tyrrell and Landis, 1994). The VAChT antiserum was generated in rabbit (Roghani et al, 1998).…”

Target-dependent specification of the neurotransmitter phenotype:cholinergic differentiation of sympathetic neurons is mediated in vivo by gp130 signaling

“…Cholinergic properties are expressed in a low number of sympathetic neurons during early embryonic development, most likely without target contact (Schäfer et al, 1997;Ernsberger et al, 1997;Stanke et al, 2000). VIP is transiently expressed in the embryonic rat superior cervical ganglion in up to 30% of the cells (Tyrrell and Landis, 1994). As the number of VIP-and VAChT-expressing cells at P0 is not affected in mice deficient for gp130, LIFR␤ or CNTFR␣, embryonic cholinergic differentiation seems not to be controlled by IL6 cytokines (this study).…”