JOURNAL ARTICLE

A novel slow excitatory postsynaptic current in substantia gelatinosa neurons of the rat spinal cord in vitro

Y Yajiri, M Yoshimura, M Okamoto, H Takahashi, H Higashi
Neuroscience 1997, 76 (3): 673-88
9135042
Whole-cell patch-clamp recordings were made from neurons in the substantia gelatinosa of adult rat spinal cord slices with attached dorsal root to study a slow synaptic current evoked by focal or dorsal root stimulation. Repetitive focal stimulation with a monopolar electrode positioned within substantia gelatinosa elicited a slow excitatory postsynaptic current preceded by a fast excitatory postsynaptic current in 73 of 83 neurons. A similar slow excitatory postsynaptic current was also elicited by stimulation of A delta afferent fibres. The amplitude of slow excitatory postsynaptic currents was unchanged when the recording electrode contained guanosine-5'-O-(2-thiodiphosphate). The slow excitatory postsynaptic current and current evoked by aspartate revealed similar reversal potentials and showed a marked outward rectification at holding potentials more negative than -30 mV, while the glutamate-induced current exhibited a relatively linear voltage relationship. In addition, the slow excitatory postsynaptic currents were reversibly occluded during the aspartate-induced current but were not occluded during the glutamate-induced current. The slow excitatory postsynaptic currents evoked by focal stimulation were depressed but not abolished by 6-cyano-7-nitroquinoxaline-2,3-dione (10 microM) or by 6-cyano-7-nitroquinoxaline-2,3-dione together with DL-2-amino-5-phosphonopentanoic acid (100 microM). Similarly, the aspartate- and glutamate-induced currents were also resistant to these antagonists. These observations suggest that a transmitter released from interneurons or descending fibres which are activated in part by A delta afferents, mediates a slow excitatory postsynaptic currents in substantia gelatinosa neurons and that an excitatory amino acid is implicated in the generation of the slow excitatory postsynaptic current, although the receptor appears to differ from the known ligand-gated channels. C afferents are unlikely to contribute to the slow excitatory postsynaptic current. This slow synaptic response may participate in the pain pathway and play an important role in the processing of nociceptive information in the spinal dorsal horn.

Full Text Links

Find Full Text Links for this Article

Discussion

You are not logged in. Sign Up or Log In to join the discussion.

Trending Papers

Remove bar
Read by QxMD icon Read
9135042
×

Save your favorite articles in one place with a free QxMD account.

×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"