Central and peripheral mechanisms of pain: Behavioral investigations
and novel therapeutical approaches in animal models
Pain represents a complex and
diversified phenomenon which starting from a foundamental function
of “alert” can
be transformed in a chronic condition, a pathology itself, strongly invalidating
life. Chronic pain is one of the more difficult health problem to be
solved with a very huge social component.
Animal models represent a great advantage for the comprehension
of physiopathological mechanisms underlying acute and chronic pain
in humans. Pain is experimentally induced through nociceptive stimuli
of different origin. Although many results on mechanisms underlying
chronic pain have recently been acquired as well as a higher aknowledge
of the great number of molecules involved, it is not established
how these molecules interact at the different levels of the nervous
system and how they are modulated by other systems.
The lack of complete knowledge of the neurobiology of pain, specifically
the passage from acute to chronic pain, is related to the lack
of pharmacological treatments. Actually, drugs represent only palliative
therapies and are often associated to tolerance and side effects.
The aim of our laboratory is to investigate, in animal models,
neural processes undelying different types of pain, specifically
inflammatory and neuropathic. Behavioral responses to thermal,
chemical and mechanical nociceptive stimuli are investigated and
the effects of pharmacological treatments acting on neuropeptides
and/or neurotransmitters involved in pain modulation are evaluated.
The study of the behavioral responses to different stimuli allows
us to take into account a number of factors influencing pain perception,
such as age, sex, environmental factors etc. Behavioral modulation
by drugs administered centrally (intracerebroventricularly or intrathecally),
systemically or peripherally, may help to specify the neural component
involved (cerebral, spinal etc.), and to improve the comprehension
of pain mechanisms.
Our approach is fundamentally a pharmacological-behavioral approach.
In addition the purpose is to correlate behavioral observations
with structural and functional changes through other investigative
approaches, e.g. immunohistochemical and immunofluorescence, carried
out in our and other laboratories through scientific cooperations.
A very new pharmacological approach recently carried out in our
laboratory with encouraging results (ref.2,4,6) is the use of
very low, not toxic doses of bacterial toxins to counteract inflammatory
and neuropathic pain.
In particolar, the working projects focuse on the investigation
of the effects of central and/or peripheral administration of :
a) different serotypes of botulinum neurotoxins (BoNTs) from Clostridium
botulinum interacting with synaptic neurotransmission (see Siro
b) the Cytotoxic Necrotizing Factor 1 (CNF1), a protein toxin from
We have demonstrated the ability of BoNT/A
to reduce formalin-induced pain as well as neuropaty induced
by sciatic nerve ligation. Work is now in progress to determine,
through immunofluorescence techniques, possible differences in
the expression of neuronal and glial markers involved in degenerative
and regenerative processes following the neuropathy induction.
When neuropathy is induced in animals, a complex process occurs
that, together with axonal degeneration, is associated to infiltration
of cells of the immune system such as macrophages and astroglia.
phenomena related to degeneration of peripheral nerves and
regeneration processes play a great role also in a therapeutic
BoNT/A (3.75, 7.5, 15 picogr/mouse, red lines) exerts analgesic
effects on both phasic and tonic phases of formalin-induced
inflammatory pain. Left: time course of licking behaviour
induced by formalin. Right: total licking time during the
first (0-10) and second (10-40) phases characterizing the
study of the intracellular signaling, e.g. p38 mitogen-activated
protein kinase (p38 MAPK) pathway, which
is critycally involved in the previous mentioned processes,
as well as macrophages' localization with mono and policlonal
antibodies, are carried out toghether with behavioural and
Analgesic effect of BoNT/A (3.75, 7.5, 15 picogr/mouse) on
neuropathic pain in mice.
The arrow indicates the injection of BoNT/A, subcutaneously administered
into the paw.
The peculiarity of the use of CNF1 in treating pain is its mecchanism of
action. CNF1 is crucially linked to the activation of the Rac GTPase,
a key regulatory protein that is switched on by the toxin, leading
to remodeling of the actin cytoskeleton in intact cells. Results obtained
provide new insights into the comprehension of inflammatory pain through
the investigation of the intracellular mechanisms involved and represent
an innovative and encouraging approach to set up a strategic treatment.
Further experiments are planned to investigate the interaction with
opioid system and the effects on neuropathic pain.
Fig.3: Mechanism of action of
With the aim to identify new drugs able to selectively modulate
pain transmission, our group, in collaboration with EBRI (European
Brain Research Institute) and LLG (Lay Line Genomics), has
focused the attention on the NGF/TrkA complex as possible target
for inhibiting pain (ref.1). The common project is still in
Flaminia Pavone (senior researcher) firstname.lastname@example.org Ph.
+39 06 501703271
Sara Marinelli (Post Doc)
Stefano Cobianchi (Phd student)
Valentina Vacca (Student)
Cecilia Eleuteri (Student)
di Neurobiologia e Medicina Molecolare, CNR
• Lay Line Genomics, Rome, Italy
• Dipartimento di Neuroscienze, Università di Tor Vergata, Rome,
• Dipartimento di Genetica e Biologia Molecolare, Università "La
Sapienza", Rome, Italy
• Dipartimento di Fisiologia, Sezione di Neuroscienze e Fisiologia Applicata,
University of Siena, Italy
• Dipartimento di Scienze Biomediche Sperimentali, University of Padua,
• European Brain Research Institute, Rome, Italy
• Drug Dept., Division of Pharmacology of Degenerative and Aging Processes,
Health High Institute, Rome,
• Institute of Pharmacology, Polish Academy of Sciences, Cracow, Poland
Capsoni S., Marinelli S., Ceci M., Vignone D., Amato G., Malerba
F., Paoletti F., Meli G., Viegi A., Pavone F., Cattaneo A.
Intranasal "painless" human Nerve Growth Factors
slows amyloid neurodegeneration and prevents memory deficits
in App X PS1 mice. PLoS One. 2012;7(5):e37555. doi: 10.1371/journal.pone.0037555.
Epub 2012 May 30.
S., Vacca V., Ricordy R., Uggenti C., Tata A.M., Luvisetto
S., Pavone F. The Analgesic Effect on Neuropathic Pain of Retrogradely
Transported botulinum Neurotoxin A Involves Schwann Cells and
Astrocytes. PLoS One. 2012;7(10):e47977. doi: 10.1371/journal.pone.0047977.
Epub 2012 Oct 24.
- De Leonibus E., Costantini V.J., Massaro
A., Mandolesi G., Vanni V., Luvisetto S., Pavone F., Oliverio
A., Mele A. Cognitive and neural determinants of response strategy
in the dual-solution plus-maze task. Learn Mem. 2011;18(4):241-4.
- Capsoni S., Covaceuszach S., Marinelli S., Ceci M., Bernardo
A., Minghetti L., Ugolini G., Pavone F., Cattaneo A. Taking
pain out of NGF: a "painless" NGF mutant, linked
to hereditary sensory autonomic neuropathy type V, with full
neurotrophic activity. PLoS One. 2011;6(2):e17321.
- Mika J., Rojewska E., Makuch W., Korostynski M., Luvisetto
S., Marinelli S., Pavone F., Przewlocka B. The effect of botulinum
neurotoxin A on sciatic nerve injury-induced neuroimmunological
changes in rat dorsal root ganglia and spinal cord. Neuroscience.
- Pavone F.,Luvisetto S.. Botulinum Neurotoxin for Pain Management:
Insights from Animal Models. Toxins 2010; 2(12), 2890-2913.
- Marinelli S., Luvisetto S., Cobianchi S., Makuch W., Obara
I., Mezzaroma E., Caruso M., Straface E., Przewlocka B., Pavone
F. Botulinum neurotoxin type A counteracts neuropathic pain
and facilitates functional recovery after peripheral nerve
injury in animal models. Neuroscience. 2010; 171(1):316-28.
- Cobianchi S., Marinelli S., Florenzano F., Pavone F., Luvisetto
S. Short- but not long-lasting treadmill running reduces allodynia
and improves functional recovery after peripheral nerve injury.
Neuroscience. 2010;168(1):273-87. Epub 2010 Mar 25.
- Nalepa I., Vetulani J., Borghi V., Kowalska M., Przewlocka
B., Roman A., Pavone F. Changes induced by formalin pain in
central alpha1-adrenoceptor density are modulated by adenosine
receptor agonists. J Neural Transm. 2010;117(5):549-58.
- Covaceuszach S., Capsoni S., Marinelli S., Pavone F., Ceci
M., Ugolini G., Vignone D., Amato G., Paoletti F., Lamba D.,
Cattaneo A. In vitro receptor binding propertiesof a "painless" NGF
mutein, linked to hereditary sensory autonomic neuropathy type
V. Biochem Biophys Res Commun. 2010;391(1):824-9.
- Ugolini G., Marinelli S., Covaceuszach
S., Cattaneo A., Pavone F. The function neutralizing anti-TrkA
antibody MNAC13 reduces inflammatory and neurophatic pain. Proc.
Natl. Acad. Sci., USA, 104(8), 2985-90, 2007.
- Luvisetto S, Marinelli S, Cobianchi S, Pavone F.: Anti-allodynic
efficacy of botulinum neurotoxin A in a model of neuropathic pain.
Neuroscience. Mar 2;145(1)1-4, 2007.
- Luvisetto S, Marinelli S, Panasiti MS, D'Amato FR, Fletcher CF, Pavone
F, Pietrobon D. Pain sensitivity in mice lacking the Ca(v)2.1alpha1
subunit of P/Q-type Ca2+ channels. Neuroscience. Oct 27;142(3), 823-32,
- Luvisetto S, Marinelli S, Lucchetti F, Marchi F, Cobianchi S, Rossetto
O, Montecucco C, Pavone F. Botulinum neurotoxins and formalin-induced
pain central vs. peripheral effects in mice. Brain Res., 1082(1), 124-31,
- Nalepa I., Vetulani J., Borghi V., Kowalska M., Przewlocka B., Pavone
F. Formalin hindpaw injection induces changes in the [(3)H]prazosin
binding to alpha(1)-adrenoceptors in specific regions of the mouse
brain and spinal cord. J. Neural Transm., 112(10), 1309-13319, 2005.
- Luvisetto S, Marinelli S, Rossetto O, Montecucco C, Pavone F. Central
injection of botulinum neurotoxins behavioural effects in mice. Behav
Pharmacol. 2004 May;15(3), 233-40.
- Borghi V., Przewlocka B., Labuz D., Maj M., Obara I., Pavone F. Formalin
induced pain and mu-opioid receptor density in brain and spinal cord
are modulated by A1 and A2a adenosine agonist in mice. Brain Research,
956 339-348, 2002.
- Capone F., Aloisi A.M., Carli G., Sacerdote P. and Pavone F. Oxotremorine-induced
modifications of the behavioral and neuroendocrine responses to formalin
pain in male rats. Brain Research, 830, 292-300, 1999.
- D'Amato F.R., Mazzacane E., Capone F., Pavone F. Effects of postnatal
manipulation on nociception and morphine sensitivity in adult mice.
Brain Res. Dev. Res., 117(1), 15-20, 1999.
- Przewlocka B., Mika J., Capone F., Machelska H. and Pavone F. Intrathecal
oxotremorine affects formalin-induced behavior and spinal nitric oxide
synthase immunoreactivity in rats. Pharmacol. Biochem and Behav. 62(3),
- "Physostigmine derivatives with
acetylcholinesterase inhibition properties, and the relative
production process"(C.N.R. Bollettino Ufficiale - Norme
tecniche e Brevetti - A.XVIII-N.98,1984) (European Patent
Inventors: Mario Brufani, Claudio Castellano, Maurizio Marta, Alberto
Oliverio, Flaminia Pavone, Massimo Pomponi.
that are able to inhibit the binding between NGF and TrkA
receptor as analgesics with prolonged effect" Italian
patent: RM2005A000290, European Patent: WO 2006/131951 A2.
Inventors: Flaminia Pavone, Sara Marinelli, Antonino Cattaneo, Gabriele
- "Method for the potentiation of opioid analgesics effects
on pain". Italian Patent:RM2005A000332. European Patent: WO
Inventors: Flaminia Pavone, Sara Marinelli, Antonino
proteici dermonecrotizzanti di origine batterica e relativi usi in
campo medico". Italian Patent: RM2005A000422.
Inventors: Alessia Fabbri, Loredana Falzano, Carla Fiorentini, Siro
Luvisetto, walter Malorni, Sara Marinelli, Flaminia Pavone, Elisabetta