Autism Studies and Related Medical Conditions, January 2009 - TACA

Reichelt K.L., Knivsberg A.M., Lind G., Nodland M.: The probable etiology and
possible treatment of childhood autism. Brain Dysfunct. 1991, 4: 308-319. [No abstract
available]
Longoni R, Spina L, Mulas A, Carboni E, Garau L, Melchiorri P, Di Chiara G: (D-
Ala2)deltorphin II: D1-dependent stereotypies and stimulation of dopamine release in
the nucleus accumbens. J Neurosci 1991 Jun;11(6):1565-76.
Abstract:
Institute of Experimental Pharmacology and Toxicology, University of Cagliari, Italy.
In order to investigate the relative role of central delta- and mu-opioid receptors in
behavior, the effects of (D-Ala2)deltorphin II, a natural delta-opioid peptide, and PL017,
a beta-casomorphin derivative specific for mu receptors, were compared after local
intracerebral and intraventricular administration. Intracerebral infusion of the two
peptides was done bilaterally in the limbic nucleus accumbens and in the ventral and
dorsal caudate putamen of freely moving rats through chronic intracerebral cannulas.
After intra-accumbens infusion, the two peptides elicited marked but opposite
behavioral effects: while (D-Ala2)deltorphin II evoked dose-dependent motor
stimulation characterized by locomotion, sniffing, and oral stereotypies, PL017 elicited
motor inhibition with rigidity and catalepsy. These effects were site specific because
they could not be evoked from the ventral or from the dorsal caudate. Low doses of
naloxone (0.1 mg/kg, s.c. ) blocked the effects of PL017 but not those of (D-
Ala2)deltorphin II, which instead were reduced by high doses of naloxone (1.0 mg/kg)
and by the putative delta-antagonist naltrindole; this drug failed to affect the catalepsy
induced by PL017. Therefore, while (D-Ala2)deltorphin II effects were delta-mediated,
PL017 effects were mu-mediated. Blockade of dopamine D1 receptors by SCH 23390
abolished (D-Ala2)deltorphin II effects, while blockade of dopamine D2 receptors by
raclopride or by haloperidol was without effect. Local application by reverse dialysis of
(D-Ala2)deltorphin II (5 microM) to the accumbens resulted in a naloxone-sensitive
increase of extracellular dopamine concentrations; these effects could not be evoked
from the caudate, nor by PL017 in the accumbens. Intracerebroventricular
administration of (D-Ala2)deltorphin II or of PL017 elicited behavioral effects
qualitatively similar to those obtained from the accumbens.
If deltorphin II is indeed present in the urine, this may explain why low doses of
naloxone are often only moderately effective at reducing autistic behaviors.
Fukudome S.-I. and Yoshikawa M.: Opioid peptides derived from wheat gluten:
Their isolation and characterization. FEBS Letters 1991, 296: 107-111.
Abstract: Four opioid peptides were isolated from the enzymatic digest of wheat
gluten. Their structures were Gly-Tyr-Tyr-Pro-Thr, Gly-Tyr-Tyr-Pro, Tyr-Gly-Gly-Trp-Leu
Autism Studies & Related Medical Conditions – TACA © Page 167