We present the measurements of gas and stellar velocity dispersions in 17 circumnuclear star-forming regions ( CNSFRs ) and the nuclei of three barred spiral galaxies : NGC 2903 , NGC 3310 and NGC 3351 from high dispersion spectra .
The stellar dispersions have been obtained from the Ca ii triplet ( CaT ) lines at \lambda \lambda 8494 , 8542 , 8662 Å , while the gas velocity dispersions have been measured by Gaussian fits to the H \beta \lambda 4861 Å and to the [ O iii ] \lambda 5007 Å lines .

The CNSFRs , with sizes of about 100 to 150 pc in diameter , are seen to be composed of several individual star clusters with sizes between 1.5 and 6.2 pc on Hubble Space Telescope ( HST ) images .
Using the stellar velocity dispersions , we have derived dynamical masses for the entire star-forming complexes and for the individual star clusters .
Values of the stellar velocity dispersions are between 31 and 73 km s ^ { -1 } .
Dynamical masses for the whole CNSFRs are between 4.9 \times 10 ^ { 6 } and 1.9 \times 10 ^ { 8 } M _ { \odot } and between 1.4 \times 10 ^ { 6 } and 1.1 \times 10 ^ { 7 } M _ { \odot } for the individual star clusters .

We have found indications for the presence of two different kinematical components in the ionized gas of the regions .
The narrow component of the two-component Gaussian fits seem to have a relatively constant value for all the studied CNSFRs , with estimated values close to 25 km s ^ { -1 } .
This narrow component could be identified with ionized gas in a rotating disc , while the stars and the fraction of the gas ( responsible for the broad component ) related to the star-forming regions would be mostly supported by dynamical pressure .