Iontophoretic application of unconjugated cholera toxin B subunit (CTb) combined with immunohistochemistry of neurochemical substances: a method for transmitter identification of retrogradely labeled neurons
Luppi P.H., Fort P., Jouvet M.
Brain Res. 534 (1-2) pages : 209-224 (1990)


Materials and Methods

Materials and Methods


(A) Injection sites

(B) Retrograde labeling

(C) Artefactual labeling due to uptake by fibers of passage

(D) Anterograde tracing

(E) Double immunostaining technique



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Figure 3B

A: overview of a section at pontine level showing a large iontophoretic injection site (2 uA, 60 min) restricted to the nucleus raphe dorsalis in a cat with 18 days of survival (case R121) The other photomicrographs of this figure illustrate examples of retrograde and anterograde labeling obtained in this case.
Bar = 2 mm.

B: low power photomicrograph showing the presence of numerous retrogradely labeled cells in the lateral habenular nucleus, indicating that the quantity of CTb in these retrogradely labeled cells rather than decreasing, increased after 18 days of survival in this well-known afferent to the nucleus raphe dorsalis.
Bar = 100 µm.

C,D: photomicrographs of retrogradely labeled neurons in the basal forebrain (C) and the insular agranular cortex (D). Note the very extensive labeling of the primary and secondary dendritic branches in the neuron shown in C and of the large dendrites of the pyramidal cells shown in D.
Bar = 50 µm.

E: photomicrograph illustrating in the median forebrain bundle the presence of two retrogradely labeled cell bodies surrounded by the bundle of anterogradely labeled fibers arising from the nucleus raphe dorsalis. Note that these fibers are passing and therefore do not display varicosities.
Bar = 100 µm.

F: photomicrograph illustrating the presence of numerous anterogradely labeled fibers with terminal-like swellings in the superficial layers of the caudal part of the pyriform cortex.
Bar = 50 µm.

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