Transneuronal spread of the pseudorabies virus after injection into the central nucleus of the amygdala in the rat.
The pseudorabies virus (PRV) is a swine alpha herpes virus that is widely used as a neural tracer because of its marked neurotropism and transneuronal transmissibility (Card et al., 1991, 1992; Strack and Loewy 1990). PRV has been used to retrogradely identify spinal cord and brainstem connections to various peripheral organs, but few anatomical studies have used CNS inoculation of PRV to investigate intrinsic brain connectivity. Improved knowledge of the mode and temporal pattern of transneuronal spread is essential for interpretation of PRV tracing studies, and is also a prerequisite to the use of this and other herpes viruses as vectors in the CNS. This study investigated the distribution of PRV labelling in the CNS at various time points after its injection into the central nucleus of the amygdala (CA). The results indicate that detection of PRV in a retrogradely labelled site at any given time after injection is not only a function of the number of synapses in the pathway from the injection site, but is also highly dependent on the axon lengths involved, much more than would be expected if fast axonal transport were the limiting factor. In addition, the window of time during which PRV may be detected in a given site is limited ultimately by neuronal destruction.
Georgetown University, USA.
L
L
Jasmin
K
K
Tarczy-Hornoch
H
H
Wang
J D
JD
Levine
A I
AI
Basbaum
D000679:Amygdala / Q000821:virology*; D000818:Animals; D002490:Central Nervous System / Q000821:virology; D011558:Herpesvirus 1, Suid / Q000502:physiology*; D007150:Immunohistochemistry; D009474:Neurons / Q000821:virology*; D051381:Rats